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Borosilicate glass is a type of
glass
Glass is a non-crystalline, often transparent, amorphous solid that has widespread practical, technological, and decorative use in, for example, window panes, tableware, and optics. Glass is most often formed by rapid cooling (quenching) of ...
with
silica
Silicon dioxide, also known as silica, is an oxide of silicon with the chemical formula , most commonly found in nature as quartz and in various living organisms. In many parts of the world, silica is the major constituent of sand. Silica is one ...
and
boron trioxide
Boron trioxide or diboron trioxide is the oxide of boron with the formula . It is a colorless transparent solid, almost always glassy (amorphous), which can be crystallized only with great difficulty. It is also called boric oxide or boria. It h ...
as the main glass-forming constituents. Borosilicate glasses are known for having very low
coefficients of thermal expansion (≈3 × 10
−6 K
−1 at 20 °C), making them more resistant to
thermal shock
Thermal shock is a type of rapidly transient mechanical load.
By definition, it is a mechanical load caused by a rapid change of temperature of a certain point.
It can be also extended to the case of a thermal gradient, which makes different par ...
than any other common glass. Such glass is subjected to less
thermal stress
In mechanics and thermodynamics, thermal stress is mechanical stress created by any change in temperature of a material. These stresses can lead to fracturing or plastic deformation depending on the other variables of heating, which include mater ...
and can withstand temperature differentials without
fracturing
Fracture is the separation of an object or material into two or more pieces under the action of stress. The fracture of a solid usually occurs due to the development of certain displacement discontinuity surfaces within the solid. If a displa ...
of about .
[ It is commonly used for the construction of ]reagent bottle
Reagent bottles, also known as media bottles or graduated bottles, are containers made of glass, plastic, borosilicate or related substances, and topped by special caps or stoppers. They are intended to contain chemicals in liquid or powder form f ...
s and flask
Flask may refer to:
Container
* Hip flask, a small container used to carry a small amount of liquid
* Laboratory flask, laboratory glassware for holding larger volumes than simple test tubes
** Erlenmeyer flask, a common laboratory flask with a ...
s as well as lighting, electronics, and cookware.
Borosilicate glass is sold under various trade names, including Borosil, Duran, Pyrex
Pyrex (trademarked as ''PYREX'' and ''pyrex'') is a brand introduced by Corning Inc. in 1915 for a line of clear, low-thermal-expansion borosilicate glass used for laboratory glassware and kitchenware. It was later expanded to include kitchenw ...
, Glassco, Supertek, Suprax, Simax, Bellco, Marinex (Brazil), BSA 60, BSC 51 (by NIPRO), Heatex, Endural, Schott, Refmex, Kimax, Gemstone Well, and MG (India).
Single ended self-starting lamps are insulated with a mica
Micas ( ) are a group of silicate minerals whose outstanding physical characteristic is that individual mica crystals can easily be split into extremely thin elastic plates. This characteristic is described as perfect basal cleavage. Mica is ...
disc and contained in a borosilicate glass gas discharge tube (arc tube) and a metal cap. They include the sodium-vapor lamp
A sodium-vapor lamp is a gas-discharge lamp that uses sodium in an excited state to produce light at a characteristic wavelength near 589 nm.
Two varieties of such lamps exist: low pressure and high pressure. Low-pressure sodium lamps are ...
that is commonly used in street lighting.
Borosilicate glass melts at about .
History
Borosilicate glass was first developed by German glassmaker Otto Schott
Friedrich Otto Schott (1851–1935) was a German chemist, glass technologist, and the inventor of borosilicate glass. Schott systematically investigated the relationship between the chemical composition of the glass and its properties. In this way ...
in the late 19th century in Jena
Jena () is a German city and the second largest city in Thuringia. Together with the nearby cities of Erfurt and Weimar, it forms the central metropolitan area of Thuringia with approximately 500,000 inhabitants, while the city itself has a popu ...
. This early borosilicate glass thus came to be known as Jena glass
Jena glass (German: ''Jenaer Glas'') is a shock- and heat-resistant glass used in scientific and technological applications, especially in chemistry.
The glass was invented by Otto Schott in 1884 in Jena, Germany, where he had established Schott ...
. After Corning Glass Works
Corning Incorporated is an American multinational technology company that specializes in specialty glass, ceramics, and related materials and technologies including advanced optics, primarily for industrial and scientific applications. The co ...
introduced Pyrex
Pyrex (trademarked as ''PYREX'' and ''pyrex'') is a brand introduced by Corning Inc. in 1915 for a line of clear, low-thermal-expansion borosilicate glass used for laboratory glassware and kitchenware. It was later expanded to include kitchenw ...
in 1915, the name became synonymous for borosilicate glass in the English-speaking world (since the 1940s, a sizable portion of glass produced under the Pyrex brand has also been made of soda-lime glass
Soda lime is a mixture of NaOH and CaO chemicals, used in granular form in closed breathing environments, such as general anaesthesia, submarines, rebreathers and recompression chambers, to remove carbon dioxide from breathing gases to prevent ...
). Borosilicate glass is the name of a glass family with various members tailored to completely different purposes. Most common today is borosilicate 3.3 or 5.0x glass such as Duran, Corning33, Corning51-V (clear), Corning51-L (amber), International Cookware's NIPRO BSA 60, and BSC 51.
Manufacturing process
Borosilicate glass is created by combining and melting boric oxide
Boron trioxide or diboron trioxide is the oxide of boron with the formula . It is a colorless transparent solid, almost always glassy (amorphous), which can be crystallized only with great difficulty. It is also called boric oxide or boria. It h ...
, silica sand, soda ash
Sodium carbonate, , (also known as washing soda, soda ash and soda crystals) is the inorganic compound with the formula Na2CO3 and its various hydrates. All forms are white, odourless, water-soluble salts that yield moderately alkaline solutions ...
, and alumina. Since borosilicate glass melts at a higher temperature than ordinary silicate glass
Glass is a non-crystalline, often transparent, amorphous solid that has widespread practical, technological, and decorative use in, for example, window panes, tableware, and optics. Glass is most often formed by rapid cooling (quenching) of ...
, some new techniques were required for industrial production.
In addition to quartz
Quartz is a hard, crystalline mineral composed of silica (silicon dioxide). The atoms are linked in a continuous framework of SiO4 silicon-oxygen tetrahedra, with each oxygen being shared between two tetrahedra, giving an overall chemical form ...
, sodium carbonate
Sodium carbonate, , (also known as washing soda, soda ash and soda crystals) is the inorganic compound with the formula Na2CO3 and its various hydrates. All forms are white, odourless, water-soluble salts that yield moderately alkaline solutions ...
, and aluminium oxide traditionally used in glassmaking
Glass production involves two main methods – the float glass process that produces sheet glass, and glassblowing that produces bottles and other containers. It has been done in a variety of ways during the history of glass.
Glass container ...
, boron
Boron is a chemical element with the symbol B and atomic number 5. In its crystalline form it is a brittle, dark, lustrous metalloid; in its amorphous form it is a brown powder. As the lightest element of the ''boron group'' it has th ...
is used in the manufacture of borosilicate glass. The composition of low-expansion borosilicate glass, such as those laboratory glasses mentioned above, is approximately 80% silica
Silicon dioxide, also known as silica, is an oxide of silicon with the chemical formula , most commonly found in nature as quartz and in various living organisms. In many parts of the world, silica is the major constituent of sand. Silica is one ...
, 13% boric oxide
Boron trioxide or diboron trioxide is the oxide of boron with the formula . It is a colorless transparent solid, almost always glassy (amorphous), which can be crystallized only with great difficulty. It is also called boric oxide or boria. It h ...
, 4% sodium oxide
Sodium oxide is a chemical compound with the formula Na2 O. It is used in ceramics and glasses. It is a white solid but the compound is rarely encountered. Instead "sodium oxide" is used to describe components of various materials such as glass ...
or potassium oxide
Potassium oxide ( K O) is an ionic compound of potassium and oxygen. It is a base. This pale yellow solid is the simplest oxide of potassium. It is a highly reactive compound that is rarely encountered. Some industrial materials, such as fertiliz ...
and 2–3% aluminium oxide. Though more difficult to make than traditional glass due to its high melting temperature, it is economical to produce. Its superior durability, chemical and heat resistance finds use in chemical
A chemical substance is a form of matter having constant chemical composition and characteristic properties. Some references add that chemical substance cannot be separated into its constituent elements by physical separation methods, i.e., wi ...
laboratory
A laboratory (; ; colloquially lab) is a facility that provides controlled conditions in which scientific or technological research, experiments, and measurement may be performed. Laboratory services are provided in a variety of settings: physicia ...
equipment, cookware, lighting, and in certain kinds of windows.
The manufacturing process depends on the product geometry and can be differentiated between different methods like floating, tube drawing Tube drawing is a process to size a tube by shrinking a large diameter tube into a smaller one, by drawing the tube through a die. This process produces high-quality tubing with precise dimensions, good surface finish, and the added strength of cold ...
, or molding.
Physical characteristics
The common type of borosilicate glass used for laboratory glassware has a very low thermal expansion
Thermal expansion is the tendency of matter to change its shape, area, volume, and density in response to a change in temperature, usually not including phase transitions.
Temperature is a monotonic function of the average molecular kinetic ...
coefficient (3.3 × 10−6 K−1), about one-third that of ordinary soda-lime glass. This reduces material stresses caused by temperature gradients, which makes borosilicate a more suitable type of glass for certain applications (see below). Fused quartz
Fused quartz, fused silica or quartz glass is a glass consisting of almost pure silica (silicon dioxide, SiO2) in amorphous (non-crystalline) form. This differs from all other commercial glasses in which other ingredients are added which change ...
ware is even better in this respect (having one-fifteenth the thermal expansion of soda-lime glass); however, the difficulty of working with fused quartz makes quartzware much more expensive, and borosilicate glass is a low-cost compromise. While more resistant to thermal shock
Thermal shock is a type of rapidly transient mechanical load.
By definition, it is a mechanical load caused by a rapid change of temperature of a certain point.
It can be also extended to the case of a thermal gradient, which makes different par ...
than other types of glass, borosilicate glass can still crack or shatter when subjected to rapid or uneven temperature variations.
Among the characteristic properties of this glass family are:
*Different borosilicate glasses cover a wide range of different thermal expansions, enabling direct seals with various metals and alloys like molybdenum
Molybdenum is a chemical element with the symbol Mo and atomic number 42 which is located in period 5 and group 6. The name is from Neo-Latin ''molybdaenum'', which is based on Ancient Greek ', meaning lead, since its ores were confused with lea ...
glass with a CTE of 4,6, tungsten
Tungsten, or wolfram, is a chemical element with the symbol W and atomic number 74. Tungsten is a rare metal found naturally on Earth almost exclusively as compounds with other elements. It was identified as a new element in 1781 and first isolat ...
with a CTE around 4,0 and Kovar
Kovar (trademark of CRS Holdings, inc., Delaware) is a nickel–cobalt ferrous alloy compositionally identical to Fernico 1, designed to have substantially the same thermal expansion characteristics as borosilicate glass (~5 × 10−6 /K between ...
with a CTE around 5,0 because of the matched CTE with the sealing partner
*Allowing high maximum temperatures of typically about
*Showing an extremely high chemical resistance in corrosive environments. Norm tests for example for acid resistance create extreme conditions and reveal very low impacts on glass
The softening point The softening point is the temperature at which a material softens beyond some arbitrary softness. It can be determined, for example, by the Vicat method (ASTM-D1525 or ISO 306), Heat Deflection Test (ASTM-D648) or a ring and ball method (ISO 4625 ...
(temperature at which viscosity
The viscosity of a fluid is a measure of its resistance to deformation at a given rate. For liquids, it corresponds to the informal concept of "thickness": for example, syrup has a higher viscosity than water.
Viscosity quantifies the inte ...
is approximately 107.6 poise
Poise may mean:
* Poise (unit), a measure of viscosity
* A concept similar to gracefulness
* Ferdinand Poise
image:Ferdinand Poise 1892.jpg,
Jean Alexandre Ferdinand Poise (3 June 1828 – 13 May 1892) was a French composer, mainly of opéra ...
) of type 7740 Pyrex is .
Borosilicate glass is less dense
Density (volumetric mass density or specific mass) is the substance's mass per unit of volume. The symbol most often used for density is ''ρ'' (the lower case Greek letter rho), although the Latin letter ''D'' can also be used. Mathematically ...
(about 2.23 g/cm3) than typical soda-lime glass due to the low atomic mass of boron. Its mean specific heat capacity at constant pressure (20–100 °C) is 0.83 J/(g⋅K), roughly one fifth of water's.
The temperature differential that borosilicate glass can withstand before fracturing is about , whereas soda-lime glass can withstand only about a change in temperature. This is why typical kitchenware made from traditional soda-lime glass will shatter if a vessel containing boiling water is placed on ice, but Pyrex or other borosilicate laboratory glass will not.
Optically, borosilicate glasses are crown glasses with low dispersion (Abbe number
In optics and lens design, the Abbe number, also known as the V-number or constringence of a transparent material, is an approximate measure of the material's dispersion (change of refractive index versus wavelength), with high values of ''V'' ind ...
s around 65) and relatively low refractive indices
In optics, the refractive index (or refraction index) of an optical medium is a dimensionless number that gives the indication of the light bending ability of that medium.
The refractive index determines how much the path of light is bent, or ...
(1.51–1.54 across the visible range).
Families
For the purposes of classification, borosilicate glass can be roughly arranged in the following groups, according to their oxide composition (in mass fractions). Characteristic of borosilicate glasses is the presence of substantial amounts of silica (SiO2) and boric oxide (B2O3, >8%) as glass network formers. The amount of boric oxide affects the glass properties in a particular way. Apart from the highly resistant varieties (B2O3 up to a maximum of 13%), there are others that – due to the different way in which the boric oxide is incorporated into the structural network – have only low chemical resistance (B2O3 content over 15%). Hence we differentiate between the following subtypes.
Non-alkaline-earth
The B2O3 content for borosilicate glass is typically 12–13% and the SiO2 content over 80%. High chemical durability and low thermal expansion (3.3 × 10−6 K−1) – the lowest of all commercial glasses for large-scale technical applications – make this a versatile glass material. High-grade borosilicate flat glasses are used in a wide variety of industries, mainly for technical applications that require either good thermal resistance, excellent chemical durability, or high light transmission in combination with a pristine surface quality. Other typical applications for different forms of borosilicate glass include glass tubing, glass piping
Within industry, piping is a system of pipes used to convey fluids (liquids and gases) from one location to another. The engineering discipline of piping design studies the efficient transport of fluid.
Industrial process piping (and accompan ...
, glass containers, etc. especially for the chemical industry.
Alkaline-earth
In addition to about 75% SiO2 and 8–12% B2O3, these glasses contain up to 5% alkaline earths
The alkaline earth metals are six chemical elements in group 2 of the periodic table. They are beryllium (Be), magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba), and radium (Ra).. The elements have very similar properties: they are al ...
and alumina (Al2O3). This is a subtype of slightly softer glasses, which have thermal expansions in the range (4.0–5.0) × 10−6 K−1.
This is not to be confused with simple borosilicate glass-alumina composites.
High-borate
Glasses containing 15–25% B2O3, 65–70% SiO2, and smaller amounts of alkalis and Al2O3 as additional components have low softening points and low thermal expansion. Sealability to metals in the expansion range of tungsten and molybdenum and high electrical insulation are their most important features. The increased B2O3 content reduces the chemical resistance; in this respect, high-borate borosilicate glasses differentiate widely from non-alkaline-earth and alkaline-earth borosilicate glasses. Among these are also borosilicate glasses that transmit UV light down to 180 nm, which combine the best of the borosilicate glass and the quartz world.[
]
Uses
Borosilicate glass has a wide variety of uses ranging from cookware to lab equipment, as well as a component of high-quality products such as implantable medical devices
A medical device is any device intended to be used for medical purposes. Significant potential for hazards are inherent when using a device for medical purposes and thus medical devices must be proved safe and effective with reasonable assura ...
and devices used in space exploration
Space exploration is the use of astronomy and space technology to explore outer space. While the exploration of space is carried out mainly by astronomers with telescopes, its physical exploration though is conducted both by robotic spacec ...
.
Health and science
Virtually all modern laboratory glassware is made of borosilicate glass. It is widely used in this application due to its chemical and thermal resistance and good optical clarity, but the glass can react with sodium hydride
Sodium hydride is the chemical compound with the empirical formula Na H. This alkali metal hydride is primarily used as a strong yet combustible base in organic synthesis. NaH is a saline (salt-like) hydride, composed of Na+ and H− ions, in co ...
upon heating to produce sodium borohydride
Sodium borohydride, also known as sodium tetrahydridoborate and sodium tetrahydroborate, is an inorganic compound with the formula Na BH4. This white solid, usually encountered as an aqueous basic solution, is a reducing agent that finds appli ...
, a common laboratory reducing agent. Fused quartz
Fused quartz, fused silica or quartz glass is a glass consisting of almost pure silica (silicon dioxide, SiO2) in amorphous (non-crystalline) form. This differs from all other commercial glasses in which other ingredients are added which change ...
is also found in some laboratory equipment when its higher melting point and transmission of UV are required (e.g. for tube furnace liners and UV cuvettes), but the cost and manufacturing difficulties associated with fused quartz make it an impractical investment for the majority of laboratory equipment.
Additionally, borosilicate tubing is used as the feedstock for the production of parenteral
A route of administration in pharmacology and toxicology is the way by which a drug, fluid, poison, or other substance is taken into the body.
Routes of administration are generally classified by the location at which the substance is applied. ...
drug packaging, such as vials and pre-filled syringe
A syringe is a simple reciprocating pump consisting of a plunger (though in modern syringes, it is actually a piston) that fits tightly within a cylindrical tube called a barrel. The plunger can be linearly pulled and pushed along the inside ...
s, as well as ampoule
An ampoule (also ampul and ampule) is a small sealed vial which is used to contain and preserve a sample, usually a solid or liquid. Ampoules are usually made of glass.
Modern ampoules are most commonly used to contain pharmaceuticals and chem ...
s and dental cartridges. The chemical resistance of borosilicate glass minimizes the migration of sodium ions from the glass matrix, thus making it well suited for injectable-drug applications. This type of glass is typically referred to as USP / EP JP Type I.
Borosilicate is widely used in implantable medical device
A medical device is any device intended to be used for medical purposes. Significant potential for hazards are inherent when using a device for medical purposes and thus medical devices must be proved safe and effective with reasonable assura ...
s such as prosthetic eyes, artificial hip joints, bone cements, dental composite materials (white fillings) and even in breast implant
A breast implant is a prosthesis used to change the size, shape, and contour of a person's breast. In reconstructive plastic surgery, breast implants can be placed to restore a natural looking breast following a mastectomy, to correct congenital ...
s.
Many implantable devices benefit from the unique advantages of borosilicate glass encapsulation. Applications include veterinary tracking devices, neurostimulators for the treatment of epilepsy, implantable drug pumps, cochlear implant
A cochlear implant (CI) is a surgically implanted neuroprosthesis that provides a person who has moderate-to-profound sensorineural hearing loss with sound perception. With the help of therapy, cochlear implants may allow for improved speech und ...
s, and physiological sensors.
Electronics
During the mid-20th century, borosilicate glass tubing was used to pipe coolants (often distilled water
Distilled water is water that has been boiled into vapor and condensed back into liquid in a separate container. Impurities in the original water that do not boil below or near the boiling point of water remain in the original container. Thus, di ...
) through high-power vacuum-tube
A vacuum tube, electron tube, valve (British usage), or tube (North America), is a device that controls electric current flow in a high vacuum between electrodes to which an electric potential difference has been applied.
The type known as a ...
–based electronic equipment, such as commercial broadcast transmitters. It was also used for the envelope material for glass transmitting tubes which operated at high temperatures.
Borosilicate glasses also have an application in the semiconductor industry
The semiconductor industry is the aggregate of companies engaged in the design and fabrication of semiconductors and semiconductor devices, such as transistors and integrated circuits. It formed around 1960, once the fabrication of semiconduct ...
in the development of microelectromechanical systems
Microelectromechanical systems (MEMS), also written as micro-electro-mechanical systems (or microelectronic and microelectromechanical systems) and the related micromechatronics and microsystems constitute the technology of microscopic devices, ...
(MEMS), as part of stacks of etched silicon wafers
A wafer is a crisp, often sweet, very thin, flat, light and dry biscuit, often used to decorate ice cream, and also used as a garnish on some sweet dishes. Wafers can also be made into cookies with cream flavoring sandwiched between them. They ...
bonded to the etched borosilicate glass.
Cookware
Cookware is another common usage for borosilicate glass, including bakeware. It is used for some measuring cups, featuring screen printed markings providing graduated measurements. Borosilicate glass is sometimes used for high-quality beverage glassware, particularly in pieces designed for hot drinks. Items made of borosilicate glass can be thin yet durable, or thicker for extra strength, and are microwave- and dishwasher-safe.
Lighting
Many high-quality flashlights use borosilicate glass for the lens. This increases light transmittance
Transmittance of the surface of a material is its effectiveness in transmitting radiant energy. It is the fraction of incident electromagnetic power that is transmitted through a sample, in contrast to the transmission coefficient, which is th ...
through the lens compared to plastics and lower-quality glass.
Several types of high-intensity discharge
High-intensity discharge lamps (HID lamps) are a type of electrical gas-discharge lamp which produces light by means of an electric arc between tungsten electrodes housed inside a translucent or transparent fused quartz or fused alumina arc tu ...
(HID) lamps, such as mercury-vapor and metal-halide lamp
A metal-halide lamp is an electrical lamp that produces light by an electric arc through a gaseous mixture of vaporized mercury and metal halides (compounds of metals with bromine or iodine). It is a type of high-intensity discharge (HID) ga ...
s, use borosilicate glass as the outer envelope material.
New lampworking
Lampworking is a type of glasswork in which a torch or lamp is used to melt the glass. Once in a molten state, the glass is formed by blowing and shaping with tools and hand movements. It is also known as flameworking or torchworking, as the moder ...
techniques led to artistic applications such as contemporary glass marble
Marble is a metamorphic rock composed of recrystallized carbonate minerals, most commonly calcite or Dolomite (mineral), dolomite. Marble is typically not Foliation (geology), foliated (layered), although there are exceptions. In geology, the ...
s. The modern studio glass
Studio glass is the modern use of glass as an artistic medium to produce sculptures or three-dimensional artworks. The glass objects created are intended to make a sculptural or decorative statement. Though usage varies, the term is properly res ...
movement has responded to color. Borosilicate is commonly used in the glassblowing
Glassblowing is a glassforming technique that involves inflating molten glass into a bubble (or parison) with the aid of a Blowpipe (tool), blowpipe (or blow tube). A person who blows glass is called a ''glassblower'', ''glassmith'', or ''gaffer'' ...
form of lampworking
Lampworking is a type of glasswork in which a torch or lamp is used to melt the glass. Once in a molten state, the glass is formed by blowing and shaping with tools and hand movements. It is also known as flameworking or torchworking, as the moder ...
and the artists create a range of products such as jewelry
Jewellery ( UK) or jewelry (U.S.) consists of decorative items worn for personal adornment, such as brooches, rings, necklaces, earrings, pendants, bracelets, and cufflinks. Jewellery may be attached to the body or the clothes. From a western ...
, kitchenware :'' For a record label, see Kitchenware Records''
Kitchenware are the tools, utensils, appliances, dishes, and cookware used in food preparation, or the serving of food. Kitchenware can also be used in order to hold or store food before or aft ...
, sculpture
Sculpture is the branch of the visual arts that operates in three dimensions. Sculpture is the three-dimensional art work which is physically presented in the dimensions of height, width and depth. It is one of the plastic arts. Durable sc ...
, as well as for artistic glass smoking pipes.
Lighting manufacturers use borosilicate glass in some of their lenses.
Organic light-emitting diodes
An organic light-emitting diode (OLED or organic LED), also known as organic electroluminescent (organic EL) diode, is a light-emitting diode (LED) in which the emissive electroluminescent layer is a film of organic compound that emits light i ...
(OLED) (for display and lighting purposes) also use borosilicate glass (BK7). The thicknesses of the BK7 glass substrates are usually less than 1 millimeter for OLED fabrication. Due to its optical and mechanical characteristics in relation with cost, BK7 is a common substrate in OLEDs. However, depending on the application, soda-lime glass
Soda lime is a mixture of NaOH and CaO chemicals, used in granular form in closed breathing environments, such as general anaesthesia, submarines, rebreathers and recompression chambers, to remove carbon dioxide from breathing gases to prevent ...
substrates of similar thicknesses are also used in OLED fabrication.
Optics
Many astronomical reflecting telescope
A reflecting telescope (also called a reflector) is a telescope that uses a single or a combination of curved mirrors that reflect light and form an image. The reflecting telescope was invented in the 17th century by Isaac Newton as an alternati ...
s use glass mirror components made of borosilicate glass because of its low coefficient of thermal expansion. This makes very precise optical surfaces possible that change very little with temperature, and matched glass mirror components that "track" across temperature changes and retain the optical system's characteristics.
The Hale Telescope's 200 inch mirror is made of borosilicate glass.
The optical glass most often used for making instrument lenses
A lens is a transmissive optical device which focuses or disperses a light beam by means of refraction. A simple lens consists of a single piece of transparent material, while a compound lens consists of several simple lenses (''elements''), ...
is Schott BK-7 (or the equivalent from other makers, such as the Chinese crown glass K9), a very finely made borosilicate crown glass.
It is also designated as 517642 glass after its 1.517 refractive index and 64.2 Abbe number
In optics and lens design, the Abbe number, also known as the V-number or constringence of a transparent material, is an approximate measure of the material's dispersion (change of refractive index versus wavelength), with high values of ''V'' ind ...
. Other less costly borosilicate glasses, such as Schott B270 or the equivalent, are used to make " crown-glass" eyeglass lenses. Ordinary lower-cost borosilicate glass, like that used to make kitchenware and even reflecting telescope mirrors, cannot be used for high-quality lenses because of the striations and inclusions common to lower grades of this type of glass. The maximal working temperature is . While it transitions to a liquid starting at (just before it turns red-hot), it is not workable until it reaches over . That means that in order to industrially produce this glass, oxygen/fuel torches must be used. Glassblowers borrowed technology and techniques from welders.
Rapid prototyping
Borosilicate glass has become the material of choice for fused deposition modeling
Fused filament fabrication (FFF), also known as fused deposition modeling (with the trademarked acronym FDM), or called ''filament freeform fabrication'', is a 3D printing process that uses a continuous filament of a thermoplastic material. Filam ...
(FDM), or fused filament fabrication (FFF), build plates. Its low coefficient of expansion makes borosilicate glass, when used in combination with resistance-heating plates and pads, an ideal material for the heated build platform onto which plastic materials are extruded one layer at a time. The initial layer of build must be placed onto a substantially flat, heated surface to minimize shrinkage of some build materials ( ABS, polycarbonate
Polycarbonates (PC) are a group of thermoplastic polymers containing carbonate groups in their chemical structures. Polycarbonates used in engineering are strong, tough materials, and some grades are optically transparent. They are easily work ...
, polyamide
A polyamide is a polymer with repeating units linked by amide bonds.
Polyamides occur both naturally and artificially. Examples of naturally occurring polyamides are proteins, such as wool and silk. Artificially made polyamides can be made through ...
, etc.) due to cooling after deposition. Depending on the material used, the build plate will cycle from room temperature to between 50 °C and 130 °C for each prototype that is built. The temperature, along with various coatings (Kapton tape
Structure of poly-oxydiphenylene-pyromellitimide
Kapton insulating pads for mounting electronic parts on a heat sink
Kapton is a polyimide film used in flexible printed circuits (flexible electronics) and space blankets, which are used on spac ...
, painter's tape, hair spray, glue stick, ABS+acetone slurry, etc.), ensure that the first layer may be adhered to and remain adhered to the plate, without warping, as the first and subsequent layers cool following extrusion. Subsequently, following the build, the heating elements and plate are allowed to cool. The resulting residual stress formed when the plastic contracts as it cools, while the glass remains relatively dimensionally unchanged due to the low coefficient of thermal expansion
Thermal expansion is the tendency of matter to change its shape, area, volume, and density in response to a change in temperature, usually not including phase transitions.
Temperature is a monotonic function of the average molecular kinetic ...
, provides a convenient aid in removing the otherwise mechanically bonded plastic from the build plate. In some cases the parts self-separate as the developed stresses overcome the adhesive bond of the build material to the coating material and underlying plate.
Other
Aquarium heaters are sometimes made of borosilicate glass. Due to its high heat resistance, it can tolerate the significant temperature difference between the water and the nichrome
Nichrome (also known as NiCr, nickel-chromium or chromium-nickel) is a family of alloys of nickel, chromium, and often iron (and possibly other elements) commonly used as resistance wire, heating elements in devices like toasters, electrical kettl ...
heating element
A heating element converts electrical energy into heat through the process of Joule heating. Electric current through the element encounters resistance, resulting in heating of the element. Unlike the Peltier effect, this process is independe ...
.
Specialty glass smoking pipes
A tobacco pipe, often called simply a pipe, is a device specifically made to smoke tobacco. It comprises a chamber (the bowl) for the tobacco from which a thin hollow stem (shank) emerges, ending in a mouthpiece. Pipes can range from very simp ...
for cannabis
''Cannabis'' () is a genus of flowering plants in the family Cannabaceae. The number of species within the genus is disputed. Three species may be recognized: ''Cannabis sativa'', '' C. indica'', and '' C. ruderalis''. Alternatively ...
and tobacco
Tobacco is the common name of several plants in the genus '' Nicotiana'' of the family Solanaceae, and the general term for any product prepared from the cured leaves of these plants. More than 70 species of tobacco are known, but the ...
can be made from borosilicate glass. The high heat resistance makes the pipes more durable. Some harm reduction
Harm reduction, or harm minimization, refers to a range of public health policies designed to lessen the negative social and/or physical consequences associated with various human behaviors, both legal and illegal. Harm reduction is used to de ...
organizations also give out borosilicate pipes intended for smoking crack cocaine
Crack cocaine, commonly known simply as crack, and also known as rock, is a free base form of the stimulant cocaine that can be smoked. Crack offers a short, intense high to smokers. The ''Manual of Adolescent Substance Abuse Treatment'' calls ...
, as the heat resistance prevents the glass from cracking, causing cuts and burns that can spread hepatitis C
Hepatitis C is an infectious disease caused by the hepatitis C virus (HCV) that primarily affects the liver; it is a type of viral hepatitis. During the initial infection people often have mild or no symptoms. Occasionally a fever, dark urine, a ...
.
Most premanufactured glass guitar slides are made of borosilicate glass.
Borosilicate is also a material of choice for evacuated-tube solar thermal technology because of its high strength and heat resistance.
The thermal insulation tiles on the Space Shuttle
The Space Shuttle is a retired, partially reusable low Earth orbital spacecraft system operated from 1981 to 2011 by the U.S. National Aeronautics and Space Administration (NASA) as part of the Space Shuttle program. Its official program na ...
were coated with a borosilicate glass.
Borosilicate glasses are used for immobilisation and disposal of radioactive waste
Radioactive waste is a type of hazardous waste that contains radioactive material. Radioactive waste is a result of many activities, including nuclear medicine, nuclear research, nuclear power generation, rare-earth mining, and nuclear weapons r ...
s. In most countries high-level radioactive waste
High-level waste (HLW) is a type of nuclear waste created by the reprocessing of spent nuclear fuel. It exists in two main forms:
* First and second cycle raffinate and other waste streams created by nuclear reprocessing.
* Waste formed by vit ...
has been incorporated into alkali borosilicate or phosphate vitreous waste forms for many years; vitrification
Vitrification (from Latin ''vitreum'', "glass" via French ''vitrifier'') is the full or partial transformation of a substance into a glass, that is to say, a non-crystalline amorphous solid. Glasses differ from liquids structurally and glasses po ...
is an established technology. Vitrification is a particularly attractive immobilization route because of the high chemical durability of the vitrified glass product. The chemical resistance of glass can allow it to remain in a corrosive environment for many thousands or even millions of years.
Borosilicate glass tubing is used in specialty TIG welding
Gas tungsten arc welding (GTAW), also known as tungsten inert gas (TIG) welding, is an arc welding process that uses a non-consumable tungsten electrode to produce the weld. The weld area and electrode are protected from oxidation or other atmo ...
torch nozzles in place of standard alumina nozzles. This allows a clear view of the arc in situations where visibility is limited.
Trade names
Borosilicate glass is offered in slightly different compositions under different trade names:
* Borofloat of Schott AG
Schott AG is a German multinational glass company specializing in the manufacture of glass and glass-ceramics. Headquartered in Mainz, Germany, it is owned by the Carl Zeiss Foundation. The company's founder and namesake, Otto Schott, is credi ...
, a borosilicate glass, which is produced to flat glass in a float process.
* Borosil, manufactured by the company of the same name, used in laboratory glassware and microwaveable kitchenware in India
* BK7 of Schott, a borosilicate glass with a high level of purity. Main use in lens and mirrors for laser, cameras and telescopes.
* Duran of DURAN Group
Duran or Durán may refer to:
Places
* Duran, Gers, a commune in France
* Durán, Ecuador
* Duran, Iran, a village in Zanjan Province, Iran
* Duran, New Mexico
* Duran, a barangay in Dumalag, Capiz, Philippines
Entertainment
* Duran (comics ...
, similar to Pyrex, Simax or Jenaer Glas.
* Corning borosilicate glass of Corning
*Fiolax
Borosilicate glass is a type of glass with silica and boron trioxide as the main glass-forming constituents. Borosilicate glasses are known for having very low coefficients of thermal expansion (≈3 × 10−6 K−1 at 20 °C), m ...
of Schott, mainly used for containers for pharmaceutical applications.
* Ilmabor of (2014 insolvency), mainly used for containers and equipment in laboratories and medicine.
* Jenaer Glas
Jena glass (German language, German: ''Jenaer Glas'') is a shock- and heat-resistant glass used in scientific and technological applications, especially in chemistry.
The glass was invented by Otto Schott in 1884 in Jena, Germany, where he had est ...
of Zwiesel Kristallglas
Kristallglas AG is a manufacturer of crystal glass located in Zwiesel, Germany.
History
Founding
On 25 November 1872 sheet glass was manufactured for the first time in a new glassworks, whose designer was the Zwiesel carter, Anton Muel ...
, formerly Schott AG. Mainly used for kitchenware.
* Kimax is the trademark for borosilicate glassware from Kimble
* Rasotherm of VEB Jenaer Glaswerk Schott & Genossen, for technical glass
* Simax of Kavalierglass a.s., Czechia, produced for both laboratory and consumer markets.
Supertek
manufacturer of scientific lab equipment and glassware.
* Willow Glass
Gorilla Glass is a brand of chemically strengthened glass developed and manufactured by Corning, now in its seventh generation. Designed to be thin, light and damage-resistant, the glass gains its surface strength, ability to contain flaws, and c ...
is an alkali free, thin and flexible borosilicate glass of Corning
* Boroux is a borosilicate glass drinking bottles.
Borosilicate nanoparticles
It was initially thought that borosilicate glass could not be formed into nanoparticle
A nanoparticle or ultrafine particle is usually defined as a particle of matter that is between 1 and 100 nanometres (nm) in diameter. The term is sometimes used for larger particles, up to 500 nm, or fibers and tubes that are less than 1 ...
s, since an unstable boron oxide Boron oxide may refer to one of several oxides of boron:
*Boron trioxide (B2O3, diboron trioxide), the most common form
*Boron monoxide (B2O), theoretical, unstable
*Boron suboxide
Boron suboxide (chemical formula B6O) is a solid compound with a s ...
precursor prevented successful forming of these shapes. However, in 2008 a team of researchers from the Swiss Federal Institute of Technology
(colloquially)
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, image = ETHZ.JPG
, image_size =
, established =
, type = Public
, budget = CHF 1.896 billion (2021)
, rector = Günther Dissertori
, president = Joël Mesot
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at Lausanne
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were successful in forming borosilicate nanoparticles of 100 to 500 nanometer
330px, Different lengths as in respect to the molecular scale.
The nanometre (international spelling as used by the International Bureau of Weights and Measures; SI symbol: nm) or nanometer (American and British English spelling differences#-re ...
s in diameter. The researchers formed a gel
A gel is a semi-solid that can have properties ranging from soft and weak to hard and tough. Gels are defined as a substantially dilute cross-linked system, which exhibits no flow when in the steady-state, although the liquid phase may still di ...
of tetraethylorthosilicate and trimethoxyboroxine. When this gel is exposed to water under proper conditions, a dynamic reaction ensues which results in the nanoparticles.
In lampworking
Borosilicate (or "boro", as it is often called) is used extensively in the glassblowing
Glassblowing is a glassforming technique that involves inflating molten glass into a bubble (or parison) with the aid of a Blowpipe (tool), blowpipe (or blow tube). A person who blows glass is called a ''glassblower'', ''glassmith'', or ''gaffer'' ...
process lampworking
Lampworking is a type of glasswork in which a torch or lamp is used to melt the glass. Once in a molten state, the glass is formed by blowing and shaping with tools and hand movements. It is also known as flameworking or torchworking, as the moder ...
; the glassworker uses a burner torch to melt and form glass, using a variety of metal and graphite
Graphite () is a crystalline form of the element carbon. It consists of stacked layers of graphene. Graphite occurs naturally and is the most stable form of carbon under standard conditions. Synthetic and natural graphite are consumed on large ...
tools to shape it. Borosilicate is referred to as "hard glass" and has a higher melting point (approximately 3,000 °F / 1648 °C) than "soft glass", which is preferred for glassblowing by beadmakers. Raw glass used in lampworking comes in glass rods for solid work and glass tubes
Glass tubes are mainly cylindrical hollow-wares. Their special shape combined with the huge variety of glass types (like borosilicate, flint, aluminosilicate, soda lime, lead or quartz glass), allows the use of glass tubing in many applications. Fo ...
for hollow work tubes and vessels/containers. Lampworking is used to make complex and custom scientific apparatus; most major universities have a lampworking shop to manufacture and repair their glassware. For this kind of "scientific glassblowing", the specifications must be exact and the glassblower must be highly skilled and able to work with precision. Lampworking is also done as art, and common items made include goblets, paper weights, pipes, pendants, compositions and figurines.
In 1968, English metallurgist John Burton brought his hobby of hand-mixing metallic oxides into borosilicate glass to Los Angeles. Burton began a glass workshop at Pepperdine College, with instructor Margaret Youd. A few of the students in the classes, including Suellen Fowler, discovered that a specific combination of oxides made a glass that would shift from amber to purples and blues, depending on the heat and flame atmosphere. Fowler shared this combination with Paul Trautman, who formulated the first small-batch colored borosilicate recipes. He then founded Northstar Glassworks in the mid-1980s, the first factory devoted solely to producing colored borosilicate glass rods and tubes for use by artists in the flame. Trautman also developed the techniques and technology to make the small-batch colored boro that is used by a number of similar companies.[Robert Mickelsen, "Art Glass Lampworking History" Online Glass Museum, http://www.theglassmuseum.com/lampwork.html]
Beadmaking
In recent years, with the resurgence of lampworking as a technique to make handmade glass beads, borosilicate has become a popular material in many glass artists' studios. Borosilicate for beadmaking comes in thin, pencil-like rods. Glass Alchemy, Trautman Art Glass, and Northstar are popular manufacturers, although there are other brands available. The metals used to color borosilicate glass, particularly silver, often create strikingly beautiful and unpredictable results when melted in an oxygen-gas torch flame. Because it is more shock-resistant and stronger than soft glass, borosilicate is particularly suited for pipe making, as well as sculpting figures and creating large beads. The tools used for making glass beads from borosilicate glass are the same as those used for making glass beads from soft glass.
References
{{DEFAULTSORT:Borosilicate Glass
Glass compositions
Boron compounds
Transparent materials
Fused filament fabrication
Low thermal expansion materials