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GLASS is a non-crystalline amorphous solid that is often transparent and has widespread practical, technological, and decorative usage in, for example, window panes, tableware , and optoelectronics . The most familiar, and historically the oldest, types of glass are "silicate glasses" based on the chemical compound silica (silicon dioxide, or quartz ), the primary constituent of sand . The term _glass_, in popular usage, is often used to refer only to this type of material, which is familiar from use as window glass and in glass bottles. Of the many silica-based glasses that exist, ordinary glazing and container glass is formed from a specific type called soda-lime glass , composed of approximately 75% silicon dioxide (SiO2), sodium oxide (Na2O) from sodium carbonate (Na2CO3), calcium oxide, also called lime (CaO), and several minor additives.

Many applications of silicate glasses derive from their optical transparency , giving rise to their primary use as window panes. Glass will transmit , reflect and refract light; these qualities can be enhanced by cutting and polishing to make optical lenses , prisms , fine glassware, and optical fibers for high speed data transmission by light. Glass
Glass
can be coloured by adding metallic salts, and can also be painted and printed with vitreous enamels . These qualities have led to the extensive use of glass in the manufacture of art objects and in particular, stained glass windows . Although brittle, silicate glass is extremely durable, and many examples of glass fragments exist from early glass-making cultures. Because glass can be formed or moulded into any shape, it has been traditionally used for vessels: bowls , vases , bottles , jars and drinking glasses. In its most solid forms it has also been used for paperweights , marbles , and beads . When extruded as glass fiber and matted as glass wool in a way to trap air, it becomes a thermal insulating material, and when these glass fibers are embedded into an organic polymer plastic , they are a key structural reinforcement part of the composite material fiberglass . Some objects historically were so commonly made of silicate glass that they are simply called by the name of the material, such as drinking glasses and reading glasses.

Scientifically, the term "glass" is often defined in a broader sense, encompassing every solid that possesses a non-crystalline (that is, amorphous ) structure at the atomic scale and that exhibits a glass transition when heated towards the liquid state. Porcelains and many polymer thermoplastics familiar from everyday use are glasses. These sorts of glasses can be made of quite different kinds of materials than silica: metallic alloys , ionic melts, aqueous solutions , molecular liquids, and polymers . For many applications, like glass bottles or eyewear , polymer glasses (acrylic glass , polycarbonate or polyethylene terephthalate ) are a lighter alternative than traditional glass.

CONTENTS

* 1 Silicate glass

* 1.1 Ingredients

* 2 Physical properties

* 2.1 Optical properties

* 2.2 Other properties

* 2.2.1 Corrosion
Corrosion

* 3 Contemporary production

* 3.1 Color

* 4 History of silicate glass

* 4.1 Chronology of advances in architectural glass

* 5 Other types

* 5.1 Fiberglass
Fiberglass
* 5.2 Network glasses * 5.3 Amorphous metals * 5.4 Electrolytes * 5.5 Aqueous solutions * 5.6 Molecular liquids * 5.7 Polymers * 5.8 Colloidal glasses * 5.9 Glass-ceramics

* 6 Structure

* 6.1 Formation from a supercooled liquid * 6.2 Behavior of antique glass

* 7 Gallery * 8 See also * 9 References * 10 External links

SILICATE GLASS

INGREDIENTS

Silica
Silica
(the chemical compound SiO2) is a common fundamental constituent of glass. In nature, vitrification of quartz occurs when lightning strikes sand , forming hollow, branching rootlike structures called fulgurite .

Fused quartz is a glass made from chemically-pure SiO2 (silica). It has excellent resistance to thermal shock , being able to survive immersion in water while red hot. However, its high melting temperature (1723 °C ) and viscosity make it difficult to work with. Normally, other substances are added to simplify processing. One is sodium carbonate (Na2CO3, "soda"), which lowers the glass-transition temperature. The soda makes the glass water-soluble , which is usually undesirable, so lime (CaO, calcium oxide , generally obtained from limestone ), some magnesium oxide (MgO) and aluminium oxide (Al2O3) are added to provide for a better chemical durability. The resulting glass contains about 70 to 74% silica by weight and is called a soda-lime glass . Soda-lime glasses account for about 90% of manufactured glass.

Most common glass contains other ingredients to change its properties. Lead glass or flint glass is more "brilliant" because the increased refractive index causes noticeably more specular reflection and increased optical dispersion . Adding barium also increases the refractive index. Thorium oxide gives glass a high refractive index and low dispersion and was formerly used in producing high-quality lenses, but due to its radioactivity has been replaced by lanthanum oxide in modern eyeglasses. Iron can be incorporated into glass to absorb infrared radiation, for example in heat-absorbing filters for movie projectors, while cerium(IV) oxide can be used for glass that absorbs UV wavelengths.

The following is a list of the more common types of silicate glasses and their ingredients, properties, and applications:

* FUSED QUARTZ, also called FUSED-SILICA GLASS, VITREOUS-SILICA GLASS: silica (SiO2) in vitreous, or glass, form (i.e., its molecules are disordered and random, without crystalline structure). It has very low thermal expansion, is very hard, and resists high temperatures (1000–1500 °C). It is also the most resistant against weathering (caused in other glasses by alkali ions leaching out of the glass, while staining it). Fused quartz is used for high-temperature applications such as furnace tubes, lighting tubes, melting crucibles, etc. * SODA-LIME-SILICA GLASS, WINDOW GLASS: silica + sodium oxide (Na2O) + lime (CaO) + magnesia (MgO) + alumina (Al2O3). Is transparent, easily formed and most suitable for window glass (see flat glass ). It has a high thermal expansion and poor resistance to heat (500–600 °C). It is used for windows, some low-temperature incandescent light bulbs, and tableware. Container glass is a soda-lime glass that is a slight variation on flat glass, which uses more alumina and calcium, and less sodium and magnesium, which are more water-soluble. This makes it less susceptible to water erosion. * SODIUM BOROSILICATE GLASS, PYREX: silica + boron trioxide (B2O3) + soda (Na2O) + alumina (Al2O3). Stands heat expansion much better than window glass. Used for chemical glassware, cooking glass, car head lamps , etc. Borosilicate glasses (e.g. Pyrex , Duran ) have as main constituents silica and boron trioxide. They have fairly low coefficients of thermal expansion (7740 Pyrex CTE is 3.25×10−6/°C as compared to about 9×10−6/°C for a typical soda-lime glass ), making them more dimensionally stable. The lower coefficient of thermal expansion (CTE) also makes them less subject to stress caused by thermal expansion , thus less vulnerable to cracking from thermal shock . They are commonly used for reagent bottles, optical components and household cookware. * LEAD-OXIDE GLASS, CRYSTAL GLASS, LEAD GLASS: silica + lead oxide (PbO) + potassium oxide (K2O) + soda (Na2O) + zinc oxide (ZnO) + alumina. Because of its high density (resulting in a high electron density), it has a high refractive index, making the look of glassware more brilliant (called "crystal", though of course it is a glass and not a crystal). It also has a high elasticity, making glassware "ring". It is also more workable in the factory, but cannot stand heating very well. This kind of glass is also more fragile than other glasses (and is easier to cut). * ALUMINOSILICATE GLASS: silica + alumina + lime + magnesia + barium oxide (BaO) + boric oxide (B2O3). Extensively used for fiberglass , used for making glass-reinforced plastics (boats, fishing rods, etc.) and for halogen bulb glass. Aluminosilicate glasses are also resistant to weathering and water erosion. * GERMANIUM-OXIDE GLASS: alumina + germanium dioxide (GeO2). Extremely clear glass, used for fiber-optic waveguides in communication networks. Light loses only 5% of its intensity through 1 km of glass fiber.

Another common glass ingredient is crushed alkali glass or "cullet" ready for recycled glass . The recycled glass saves on raw materials and energy. Impurities in the cullet can lead to product and equipment failure. Fining agents such as sodium sulfate , sodium chloride , or antimony oxide may be added to reduce the number of air bubbles in the glass mixture. Glass batch calculation is the method by which the correct raw material mixture is determined to achieve the desired glass composition.

*

Moldavite , a natural glass formed by meteorite impact, from Besednice , Bohemia *

Tube fulgurites *

Quartz
Quartz
sand (silica) is the main raw material in commercial glass production *

Trinitite , a glass made by the Trinity nuclear-weapon test *

Lead glass a glass made by adding lead oxide to glass *

A borosilicate glass container

PHYSICAL PROPERTIES

See also: List of physical properties of glass

OPTICAL PROPERTIES

Glass
Glass
is in widespread use largely due to the production of glass compositions that are transparent to visible light. In contrast, polycrystalline materials do not generally transmit visible light. The individual crystallites may be transparent, but their facets (grain boundaries ) reflect or scatter light resulting in diffuse reflection . Glass
Glass
does not contain the internal subdivisions associated with grain boundaries in polycrystals and hence does not scatter light in the same manner as a polycrystalline material. The surface of a glass is often smooth since during glass formation the molecules of the supercooled liquid are not forced to dispose in rigid crystal geometries and can follow surface tension , which imposes a microscopically smooth surface. These properties, which give glass its clearness, can be retained even if glass is partially light-absorbing—i.e., colored.

Glass
Glass
has the ability to refract, reflect, and transmit light following geometrical optics , without scattering it (due to the absence of grain boundaries). It is used in the manufacture of lenses and windows. Common glass has a refraction index around 1.5. This may be modified by adding low-density materials such as boron, which lowers the index of refraction (see crown glass ), or increased (to as much as 1.8) with high-density materials such as (classically) lead oxide (see flint glass and lead glass ), or in modern uses, less toxic oxides of zirconium , titanium , or barium . These high-index glasses (inaccurately known as "crystal" when used in glass vessels) cause more chromatic dispersion of light, and are prized for their diamond-like optical properties.

According to Fresnel equations
Fresnel equations
, the reflectivity of a sheet of glass is about 4% per surface (at normal incidence in air), and the transmissivity of one element (two surfaces) is about 90%. Glass
Glass
with high germanium oxide content also finds application in optoelectronics —e.g., for light-transmitting optical fibers .

*

A wine glass *

Simple optical device: the magnifying glass *

Glass
Glass
petri dish *

A glass cup

OTHER PROPERTIES

In the process of manufacture, silicate glass can be poured, formed, extruded and molded into forms ranging from flat sheets to highly intricate shapes. The finished product is brittle and will fracture, unless laminated or specially treated, but is extremely durable under most conditions. It erodes very slowly and can mostly withstand the action of water. It is mostly resistant to chemical attack, does not react with foods, and is an ideal material for the manufacture of containers for foodstuffs and most chemicals. Glass
Glass
is also a fairly inert substance.

Corrosion

Main article: Corrosion
Corrosion
§ Corrosion
Corrosion
of glasses

Although glass is generally corrosion -resistant and more corrosion resistant than other materials, it still can be corroded. The materials that make up a particular glass composition has an effect on how quickly the glass corrodes. A glass containing a high proportion of alkalis or alkali earths is less corrosion-resistant than other glasses.

CONTEMPORARY PRODUCTION

Main articles: Glass production , Float glass , Flat glass , Glassblowing , and Glazier

Following the glass batch preparation and mixing, the raw materials are transported to the furnace. Soda-lime glass for mass production is melted in gas fired units . Smaller scale furnaces for specialty glasses include electric melters, pot furnaces, and day tanks. After melting, homogenization and refining (removal of bubbles), the glass is formed . Flat glass for windows and similar applications is formed by the float glass process, developed between 1953 and 1957 by Sir Alastair Pilkington and Kenneth Bickerstaff of the UK's Pilkington Brothers, who created a continuous ribbon of glass using a molten tin bath on which the molten glass flows unhindered under the influence of gravity. The top surface of the glass is subjected to nitrogen under pressure to obtain a polished finish. Container glass for common bottles and jars is formed by blowing and pressing methods. This glass is often slightly modified chemically (with more alumina and calcium oxide) for greater water resistance. Further glass forming techniques are summarized in the table Glass
Glass
forming techniques .

Once the desired form is obtained, glass is usually annealed for the removal of stresses and to increase the glass's hardness and durability. Surface treatments, coatings or lamination may follow to improve the chemical durability (glass container coatings , glass container internal treatment ), strength (toughened glass , bulletproof glass , windshields ), or optical properties (insulated glazing , anti-reflective coating ).

*

Impurities give the glass its color *

Some of the many color possibilities of glass *

Transparent and opaque examples *

Glass
Glass
can be blown into an infinite number of shapes

COLOR

Main article: Glass coloring and color marking

Color in glass may be obtained by addition of electrically charged ions (or color centers ) that are homogeneously distributed, and by precipitation of finely dispersed particles (such as in photochromic glasses ). Ordinary soda-lime glass appears colorless to the naked eye when it is thin, although iron(II) oxide (FeO) impurities of up to 0.1 wt% produce a green tint, which can be viewed in thick pieces or with the aid of scientific instruments. Further FeO and Cr2O3 additions may be used for the production of green bottles. Sulfur
Sulfur
, together with carbon and iron salts, is used to form iron polysulfides and produce amber glass ranging from yellowish to almost black. A glass melt can also acquire an amber color from a reducing combustion atmosphere. Manganese dioxide can be added in small amounts to remove the green tint given by iron(II) oxide. When used in art glass or studio glass is colored using closely guarded recipes that involve specific combinations of metal oxides, melting temperatures and "cook" times. Most colored glass used in the art market is manufactured in volume by vendors who serve this market, although there are some glassmakers with the ability to make their own color from raw materials.

HISTORY OF SILICATE GLASS

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Main article: History of glass See also: Architectural glass , Stained glass
Stained glass
, Glass art , Art glass , and Studio glass Bohemian flashed and engraved ruby glass (19th-century) Wine goblet , mid-19th century. Qajar
Qajar
dynasty. Brooklyn Museum
Brooklyn Museum
. Roman cage cup from the 4th century CE Studio glass . Multiple colors within a single object increase the difficulty of production, as glasses of different colors have different chemical and physical properties when molten.

Naturally occurring glass, especially the volcanic glass obsidian , was used by many Stone Age
Stone Age
societies across the globe for the production of sharp cutting tools and, due to its limited source areas, was extensively traded. But in general, archaeological evidence suggests that the first true glass was made in coastal north Syria, Mesopotamia
Mesopotamia
or ancient Egypt . The earliest known glass objects, of the mid third millennium BCE, were beads, perhaps initially created as accidental by-products of metal-working (slags ) or during the production of faience , a pre-glass vitreous material made by a process similar to glazing.

Glass
Glass
remained a luxury material, and the disasters that overtook Late Bronze Age civilizations seem to have brought glass-making to a halt. Indigenous development of glass technology in South Asia
South Asia
may have begun in 1730 BCE. In ancient China, though, glassmaking seems to have a late start, compared to ceramics and metal work. The term _glass_ developed in the late Roman Empire
Roman Empire
. It was in the Roman glassmaking center at Trier
Trier
, now in modern Germany, that the late-Latin term _glesum_ originated, probably from a Germanic word for a transparent , lustrous substance. Glass
Glass
objects have been recovered across the Roman Empire
Roman Empire
in domestic, funerary , and industrial contexts. Examples of Roman glass
Roman glass
have been found outside of the former Roman Empire
Roman Empire
in China
China
, the Baltics , the Middle East
Middle East
and India
India
.

Glass
Glass
was used extensively during the Middle Ages
Middle Ages
. Anglo-Saxon glass has been found across England
England
during archaeological excavations of both settlement and cemetery sites. Glass
Glass
in the Anglo-Saxon period was used in the manufacture of a range of objects including vessels, windows, beads, and was also used in jewelry. From the 10th-century onwards, glass was employed in stained glass windows of churches and cathedrals , with famous examples at Chartres Cathedral and the Basilica of Saint Denis . By the 14th-century, architects were designing buildings with walls of stained glass such as Sainte-Chapelle , Paris, (1203–1248) and the East end of Gloucester Cathedral . Stained glass
Stained glass
had a major revival with Gothic Revival architecture in the 19th-century. With the Renaissance, and a change in architectural style, the use of large stained glass windows became less prevalent. The use of domestic stained glass increased until most substantial houses had glass windows. These were initially small panes leaded together, but with the changes in technology, glass could be manufactured relatively cheaply in increasingly larger sheets. This led to larger window panes, and, in the 20th-century, to much larger windows in ordinary domestic and commercial buildings.

In the 20th century, new types of glass such as laminated glass , reinforced glass and glass bricks increased the use of glass as a building material and resulted in new applications of glass. Multi-story buildings are frequently constructed with curtain walls made almost entirely of glass. Similarly, laminated glass has been widely applied to vehicles for windscreens. While glass containers have always been used for storage and are valued for their hygienic properties, glass has been utilized increasingly in industry. Optical glass for spectacles has been used since the Middle Ages. The production of lenses has become increasingly proficient, aiding astronomers as well as having other application in medicine and science. Glass
Glass
is also employed as the aperture cover in many solar energy collectors.

From the 19th century, there was a revival in many ancient glass-making techniques including cameo glass , achieved for the first time since the Roman Empire
Roman Empire
and initially mostly used for pieces in a neo-classical style. The Art Nouveau
Art Nouveau
movement made great use of glass, with René Lalique , Émile Gallé , and Daum of Nancy producing colored vases and similar pieces, often in cameo glass, and also using luster techniques. Louis Comfort Tiffany
Louis Comfort Tiffany
in America specialized in stained glass, both secular and religious, and his famous lamps. The early 20th-century saw the large-scale factory production of glass art by firms such as Waterford and Lalique . From about 1960 onwards, there have been an increasing number of small studios hand-producing glass artworks, and glass artists began to class themselves as in effect sculptors working in glass, and their works as part fine arts .

In the 21st century, scientists are observing the properties of ancient stained glass windows, in which suspended nanoparticles prevent UV light from causing chemical reactions that change image colors, are developing photographic techniques that use similar stained glass to capture true color images of Mars
Mars
for the 2019 ESA Mars
Mars
Rover mission.

CHRONOLOGY OF ADVANCES IN ARCHITECTURAL GLASS

* 1226: "Broad Sheet " first produced in Sussex
Sussex
. * 1330: "Crown glass " for art work and vessels first produced in Rouen
Rouen
, France
France
. "Broad Sheet" also produced. Both were also supplied for export. * 1500s: A method of making mirrors out of plate glass was developed by Venetian glassmakers on the island of Murano
Murano
, who covered the back of the glass with a mercury-tin amalgam , obtaining near-perfect and undistorted reflection. * 1620s: "Blown plate" first produced in London. Used for mirrors and coach plates. * 1678: "Crown glass" first produced in London. This process dominated until the 19th century. * 1843: An early form of "float glass" invented by Henry Bessemer , pouring glass onto liquid tin. Expensive and not a commercial success. * 1874: Tempered glass is developed by Francois Barthelemy Alfred Royer de la Bastie (1830–1901) of Paris
Paris
, France
France
by quenching almost molten glass in a heated bath of oil or grease. * 1888: Machine-rolled glass introduced, allowing patterns. * 1898: Wired-cast glass first commercially produced by Pilkington
Pilkington
for use where safety or security was an issue. * 1959: Float glass launched in UK. Invented by Sir Alastair Pilkington
Pilkington
.

*

Mouth-blown window-glass in Sweden
Sweden
Kosta Glasbruk , (1742) with a pontil mark from the glassblower\'s pipe *

A building in Canterbury
Canterbury
, England
England
, which displays its long history in different building styles and glazing of every century from the 16th to the 20th included. *

Windows in the choir of the Basilica of Saint Denis , one of the earliest uses of extensive areas of glass. (early 13th-century architecture with restored glass of the 19th century) *

_" Hardwick Hall , more glass than wall"_. (late 16th century) *

Windows at Österreichische Postsparkasse, Vienna, (early 20th century) *

Westin Bonaventure Hotel, USA, show the extensive use of glass as a building material in the 20th–21st centuries

OTHER TYPES

New chemical glass compositions or new treatment techniques can be initially investigated in small-scale laboratory experiments. The raw materials for laboratory-scale glass melts are often different from those used in mass production because the cost factor has a low priority. In the laboratory mostly pure chemicals are used. Care must be taken that the raw materials have not reacted with moisture or other chemicals in the environment (such as alkali or alkaline earth metal oxides and hydroxides, or boron oxide ), or that the impurities are quantified (loss on ignition). Evaporation losses during glass melting should be considered during the selection of the raw materials, e.g., sodium selenite may be preferred over easily evaporating SeO2 . Also, more readily reacting raw materials may be preferred over relatively inert ones, such as Al(OH)3 over Al2O3 . Usually, the melts are carried out in platinum crucibles to reduce contamination from the crucible material. Glass
Glass
homogeneity is achieved by homogenizing the raw materials mixture (glass batch ), by stirring the melt, and by crushing and re-melting the first melt. The obtained glass is usually annealed to prevent breakage during processing.

To make glass from materials with poor glass forming tendencies, novel techniques are used to increase cooling rate, or reduce crystal nucleation triggers. Examples of these techniques include aerodynamic levitation (cooling the melt whilst it floats on a gas stream), splat quenching (pressing the melt between two metal anvils) and roller quenching (pouring the melt through rollers). Some glass fibers

FIBERGLASS

Main article: Fiberglass
Fiberglass
See also: Glass wool and Fiber-reinforced plastic

Fiberglass
Fiberglass
(also called glass-reinforced-plastic ) is a composite material made up of glass fibers (also called fiberglass or glass friller ) embedded in a plastic resin . It is made by melting glass and stretching the glass into fibers. These fibers are woven together into a cloth and left to set in a plastic resin.

Fiberglass
Fiberglass
filaments are made through a pultrusion process in which the raw materials (sand , limestone , kaolin clay , fluorspar , colemanite , dolomite and other minerals) are melted in a large furnace into a liquid which is extruded through very small orifices (5–25 micrometres in diameter if the glass is E-glass and 9 micrometers if the glass is S-glass ).

Fiberglass
Fiberglass
has the properties of being lightweight and corrosion resistant. Fiberglass
Fiberglass
is also a good insulator , allowing it to be used to insulate buildings. Most fiberglasses are not alkali resistant. Fiberglass
Fiberglass
also has the property of becoming stronger as the glass ages.

NETWORK GLASSES

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A CD-RW (CD). Chalcogenide glasses form the basis of rewritable CD and DVD solid-state memory technology.

Some glasses that do not include silica as a major constituent may have physico-chemical properties useful for their application in fiber optics and other specialized technical applications. These include fluoride glasses , aluminosilicates , phosphate glasses , borate glasses , and chalcogenide glasses .

There are three classes of components for oxide glasses: network formers, intermediates, and modifiers. The network formers (silicon, boron, germanium) form a highly cross-linked network of chemical bonds. The intermediates (titanium, aluminium, zirconium, beryllium, magnesium, zinc) can act as both network formers and modifiers, according to the glass composition. The modifiers (calcium, lead, lithium, sodium, potassium) alter the network structure; they are usually present as ions, compensated by nearby non-bridging oxygen atoms, bound by one covalent bond to the glass network and holding one negative charge to compensate for the positive ion nearby. Some elements can play multiple roles; e.g. lead can act both as a network former (Pb4+ replacing Si4+), or as a modifier.

The presence of non-bridging oxygens lowers the relative number of strong bonds in the material and disrupts the network, decreasing the viscosity of the melt and lowering the melting temperature.

The alkali metal ions are small and mobile; their presence in glass allows a degree of electrical conductivity , especially in molten state or at high temperature. Their mobility decreases the chemical resistance of the glass, allowing leaching by water and facilitating corrosion. Alkaline earth ions, with their two positive charges and requirement for two non-bridging oxygen ions to compensate for their charge, are much less mobile themselves and also hinder diffusion of other ions, especially the alkalis. The most common commercial glasses contain both alkali and alkaline earth ions (usually sodium and calcium), for easier processing and satisfying corrosion resistance. Corrosion
Corrosion
resistance of glass can be increased by dealkalization , removal of the alkali ions from the glass surface by reaction with e.g. sulfur or fluorine compounds. Presence of alkaline metal ions has also detrimental effect to the loss tangent of the glass, and to its electrical resistance ; glasses for electronics (sealing, vacuum tubes, lamps ...) have to take this in account.

Addition of lead(II) oxide lowers melting point, lowers viscosity of the melt, and increases refractive index . Lead oxide also facilitates solubility of other metal oxides and is used in colored glasses. The viscosity decrease of lead glass melt is very significant (roughly 100 times in comparison with soda glasses); this allows easier removal of bubbles and working at lower temperatures, hence its frequent use as an additive in vitreous enamels and glass solders . The high ionic radius of the Pb2+ ion renders it highly immobile in the matrix and hinders the movement of other ions; lead glasses therefore have high electrical resistance, about two orders of magnitude higher than soda-lime glass (108.5 vs 106.5 Ω⋅cm, DC at 250 °C). For more details, see lead glass .

Addition of fluorine lowers the dielectric constant of glass. Fluorine is highly electronegative and attracts the electrons in the lattice, lowering the polarizability of the material. Such silicon dioxide-fluoride is used in manufacture of integrated circuits as an insulator. High levels of fluorine doping lead to formation of volatile SiF2O and such glass is then thermally unstable. Stable layers were achieved with dielectric constant down to about 3.5–3.7.

AMORPHOUS METALS

Main article: Amorphous metal Samples of amorphous metal, with millimeter scale

In the past, small batches of amorphous metals with high surface area configurations (ribbons, wires, films, etc.) have been produced through the implementation of extremely rapid rates of cooling. This was initially termed "splat cooling" by doctoral student W. Klement at Caltech, who showed that cooling rates on the order of millions of degrees per second is sufficient to impede the formation of crystals, and the metallic atoms become "locked into" a glassy state. Amorphous metal wires have been produced by sputtering molten metal onto a spinning metal disk. More recently a number of alloys have been produced in layers with thickness exceeding 1 millimeter. These are known as bulk metallic glasses (BMG). Liquidmetal Technologies sell a number of zirconium-based BMGs. Batches of amorphous steel have also been produced that demonstrate mechanical properties far exceeding those found in conventional steel alloys.

In 2004, NIST
NIST
researchers presented evidence that an isotropic non-crystalline metallic phase (dubbed "q-glass") could be grown from the melt. This phase is the first phase, or "primary phase", to form in the Al-Fe-Si system during rapid cooling. Interestingly, experimental evidence indicates that this phase forms by a _first-order transition_. Transmission electron microscopy (TEM) images show that the q-glass nucleates from the melt as discrete particles, which grow spherically with a uniform growth rate in all directions. The diffraction pattern shows it to be an isotropic glassy phase. Yet there is a nucleation barrier, which implies an interfacial discontinuity (or internal surface) between the glass and the melt.

ELECTROLYTES

Electrolytes or molten salts are mixtures of different ions . In a mixture of three or more ionic species of dissimilar size and shape, crystallization can be so difficult that the liquid can easily be supercooled into a glass. The best-studied example is Ca0.4K0.6(NO3)1.4. Glass
Glass
electrolytes in the form of Ba-doped Li-glass and Ba-doped Na-glass have been proposed as solutions to problems identified with organic liquid electrolytes used in modern lithium-ion battery cells.

AQUEOUS SOLUTIONS

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Some aqueous solutions can be supercooled into a glassy state, for instance LiCl:_R_H2O in the composition range 4v * t * e

Glass
Glass
science topics

BASICS

* Glass * Glass transition * Supercooling

FORMULATION

* AgInSbTe * Bioglass * Borophosphosilicate glass * Borosilicate glass * Ceramic
Ceramic
glaze * Chalcogenide glass * Cobalt glass * Cranberry glass * Crown glass * Flint glass * Fluorosilicate glass * Fused quartz * GeSbTe * Gold ruby glass * Lead glass * Milk glass
Milk glass
* Phosphosilicate glass * Photochromic lens glass * Silicate glass * Soda-lime glass * Sodium hexametaphosphate
Sodium hexametaphosphate
* Soluble glass * Tellurite glass * Thoriated glass * Ultra low expansion glass * Uranium glass * Vitreous enamel * Wood\'s glass * ZBLAN

GLASS-CERAMICS

* Bioactive glass * CorningWare
CorningWare
* Glass-ceramic-to-metal seals * Macor * Zerodur

PREPARATION

* Annealing * Chemical
Chemical
vapor deposition * Glass batch calculation * Glass
Glass
forming * Glass
Glass
melting * Glass
Glass
modeling * Ion
Ion
implantation * Liquidus temperature * Sol-gel technique * Viscosity * Vitrification
Vitrification

OPTICS

* Achromat * Dispersion * Gradient-index optics * Hydrogen darkening * Optical amplifier * Optical fiber * Optical lens design * Photochromic lens * Photosensitive glass * Refraction
Refraction
* Transparent materials
Transparent materials

Surface modification

* Anti-reflective coating * Chemically strengthened glass * Corrosion
Corrosion
* Dealkalization * DNA microarray * Hydrogen darkening * Insulated glazing * Porous glass * Self-cleaning glass * Sol-gel technique * Toughened glass

Diverse topics

* Glass-coated wire * Safety glass * Glass databases * Glass electrode * Glass fiber reinforced concrete * Glass ionomer cement * Glass
Glass
microspheres * Glass-reinforced plastic * Glass-to-metal seal * Porous glass * Prince Rupert\'s Drops * Radioactive waste vitrification * Windshield
Windshield
* Glass fiber

* v * t * e

Glass production techniques

COMMERCIAL TECHNIQUES

* Float glass process * Blowing and pressing (containers) * Extrusion / Drawing (fibers, glasswool) * Drawing (optical fibers) * Precision glass moulding * Overflow downdraw method * Pressing * Casting * Cutting * Flame polishing * Chemical
Chemical
polishing * Diamond turning * Rolling

ARTISTIC AND HISTORIC TECHNIQUES

* Beadmaking * Blowing * Blown plate * Broad sheet * Caneworking * Cased glass * Crown glass * Cylinder blown sheet * Engraving * Etching * Flashed glass * Fourcault process * Fusing * Lampworking * Machine drawn cylinder sheet * Millefiori * Polished plate * Satsuma Kiriko cut glass * Slumping * Stained glass
Stained glass
fusing * Stained glass
Stained glass
production

NATURAL PROCESSES

* Radiative processes * Opal
Opal
formation * Sea glass * Shock metamorphic glasses / Impactite * Vitrified sand * Volcanic glasses

SEE ALSO

* Glossary of glass art terms * Glass recycling

* v * t * e

Glass
Glass
makers and brands

Contemporary companies

* Anchor Hocking * Arc International * Ardagh Group * Armashield * Asahi * Aurora Glass Foundry * Aventas group * Baccarat * Berengo Studio * Blenko Glass Company * Bodum * Bormioli Rocco * Borosil * Caithness Glass * Cox & Barnard * Corning * Dartington Crystal
Dartington Crystal
* Daum * Edinburgh Crystal
Edinburgh Crystal
* Effetre International * Fanavid * Fenton Art Glass Company * Firozabad glass industry * Flabeg * Franz Mayer * Glava * Glaverbel * Guardian Industries * Hadeland * Hardman & Co. * Heaton, Butler and Bayne * Holmegaard Glassworks * Holophane * Hoya * Kingdom of Crystal * Kokomo Opalescent Glass Works * Kosta Glasbruk * Libbey-Owens-Ford * Liuli Gongfang * Iittala * Luoyang * Johns Manville * Mats Jonasson Målerås * Moser Glass
Glass
* Mosser Glass * Nippon Sheet Glass
Nippon Sheet Glass
* Ohara * Orrefors * Osram
Osram
* Owens Corning * Owens-Illinois * Paşabahçe * Pauly & C. - Compagnia Venezia Murano
Murano
* Phu Phong * Pilkington
Pilkington
* PPG Industries * Preciosa * Riedel * Rona * Royal Leerdam Crystal * Saint-Gobain * Saint-Louis * Şişecam * Schott * Sterlite Optical Technologies * Steuben * Swarovski
Swarovski
* Tyrone Crystal
Tyrone Crystal
* Val Saint Lambert * Verrerie of Brehat
Verrerie of Brehat
* Waterford * Watts border-left-width:2px;border-left-style:solid;width:100%;padding:0px">

* Bakewell Glass * Belmont Glass Company * Boston and Sandwich Glass Company
Boston and Sandwich Glass Company
* Brockway Glass * Carr Lowrey Glass Company * Cambridge Glass * Chance Brothers * Clayton and Bell * Dugan Glass Company * Duncan & Miller * Dunbar Glass * Fostoria Glass Company * General Glass Industries * Gus Crystal * Alexander Gibbs * Grönvik glasbruk * Hartford City Glass Company
Hartford City Glass Company
* Hazel-Atlas * Heisey * Hemingray Glass Company * J. H. Hobbs, Brockunier and Company
J. H. Hobbs, Brockunier and Company
* Knox Glass
Glass
Bottle
Bottle
Company * Lavers, Barraud and Westlake * Manufacture royale de glaces de miroirs * Millersburg Glass Company * Morris & Co. * Nachtmann * Northwood Glass Company * Novelty Glass Company * Old Dominion Glass Company * James Powell and Sons * Ravenhead glass * The Root Glass Company * Seneca Glass Company * Shrigley and Hunt * Sneath Glass Company * Venini border-left-width:2px;border-left-style:solid;width:100%;padding:0px">

* John Adams * Richard M. Atwater * Frederick Carder * Irving Wightman Colburn * Henry Crimmel
Henry Crimmel
* Friedrich * Henry Clay Fry * A. H. Heisey * Edward D. Libbey * Dante Marioni * Antonio Neri * Michael Joseph Owens * Alastair Pilkington * Flavio Poli * Salviati * Otto Schott
Otto Schott
* Henry William Stiegel * S. Donald Stookey * Lino Tagliapietra * W. E. S. Turner * Tomasz Urbanowicz * Paolo Venini * John M. Whitall

Trademarks and brands

* Activ * Bohemian glass * Bomex * Duran * Endural * Burmese glass * Chevron bead * Corelle * CorningWare
CorningWare
* Cranberry glass * Cristallo * Dragontrail * Favrile * Fire-King * Forest glass * Gorilla Glass * Macor * Millefiori * Murano
Murano
glass * Opaline glass * Peking glass
Peking glass
* Pyrex * Rona * Ravenhead glass * Satsuma Kiriko cut glass * Tiffany glass * Vitrite * Vitrolite * Vycor * Waterford Crystal * Wood\'s glass * Zerodur

Related articles

* List of defunct glassmaking companies

AUTHORITY CONTROL

* LCCN : sh85055102 * GND : 4021142-3 * BNF : cb119383603 (data) * NDL : 00562246

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Glass
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