Editing Glass (section)

=== Non-silicate glasses ===
[[File:CD-RW bottom.jpg|thumb|A [[CD-RW]] (CD). [[Chalcogenide glass]] forms the basis of rewritable CD and DVD solid-state memory technology.<ref name="Greer05">{{cite journal |last1=Greer |first1=A. Lindsay |doi=10.1038/4371246a |journal=Nature |volume=437 |pages=1246–1247 |year=2005 |title=Materials science: Changing Face of the Chameleon |pmid=16251941 |last2=Mathur |first2=N |issue=7063 |bibcode=2005Natur.437.1246G|s2cid=6972351 |doi-access=free }}</ref>|alt=A CD]]
Besides common silica-based glasses many other [[inorganic]] and [[Organic chemistry|organic]] materials may also form glasses, including [[Metallic glass|metals]], [[aluminate]]s, [[phosphate]]s, [[borate]]s, [[chalcogenide glass|chalcogenides]], [[fluoride]]s, germanates (glasses based on [[Germanium oxide|GeO<sub>2</sub>]]), tellurites (glasses based on TeO<sub>2</sub>), antimonates (glasses based on Sb<sub>2</sub>O<sub>3</sub>), arsenates (glasses based on As<sub>2</sub>O<sub>3</sub>), titanates (glasses based on TiO<sub>2</sub>), tantalates (glasses based on Ta<sub>2</sub>O<sub>5</sub>), [[nitrate]]s, [[carbonate]]s, [[plastics]], [[acrylic glass|acrylic]], and many other substances.<ref name="Elliot84" /> Some of these glasses (e.g. [[Germanium dioxide]] (GeO<sub>2</sub>, Germania), in many respects a structural analogue of silica, [[fluoride glass|fluoride]], [[aluminate]], [[phosphate glass|phosphate]], [[borate glass|borate]], and [[chalcogenide glass|chalcogenide]] glasses) have physicochemical properties useful for their application in [[Optical fiber|fibre-optic]] [[waveguide]]s in communication networks and other specialised technological applications.<ref>{{Cite book|url=https://books.google.com/books?id=gL-RDgAAQBAJ&pg=PA214|title=Technological Advances in Tellurite Glasses: Properties, Processing, and Applications|last1=Rivera|first1=V. A. G.|last2=Manzani|first2=Danilo|date=2017-03-30|publisher=Springer|isbn=978-3-319-53038-3|page=214|language=en}}</ref><ref>{{Cite journal
  |last1=Jiang|first1=Xin|last2=Lousteau|first2=Joris|last3=Richards|first3=Billy|last4=Jha|first4=Animesh|date=2009-09-01
  |title=Investigation on germanium oxide-based glasses for infrared optical fibre development
  |journal=Optical Materials|volume=31|issue=11|pages=1701–1706|doi=10.1016/j.optmat.2009.04.011  |bibcode=2009OptMa..31.1701J
}}</ref>

Silica-free glasses may often have poor glass-forming tendencies. Novel techniques, including containerless processing by [[aerodynamic levitation]] (cooling the melt whilst it floats on a gas stream) or [[splat quenching]] (pressing the melt between two metal anvils or rollers), may be used to increase the cooling rate or to reduce crystal nucleation triggers.<ref>{{cite journal|author1=J. W. E. Drewitt|author2=S. Jahn|author3=L. Hennet|title=Configurational constraints on glass formation in the liquid calcium aluminate system|journal=Journal of Statistical Mechanics: Theory and Experiment|year=2019|volume=2019|issue=10|page=104012|doi=10.1088/1742-5468/ab47fc|arxiv=1909.07645|bibcode=2019JSMTE..10.4012D|s2cid=202583753}}</ref><ref>{{cite journal|author1=C. J. Benmore |author2=J. K. R. Weber|year=2017|title=Aerodynamic levitation, supercooled liquids and glass formation|journal=Advances in Physics: X|volume=2|issue=3|pages=717–736|doi= 10.1080/23746149.2017.1357498|bibcode=2017AdPhX...2..717B|doi-access=free}}</ref><ref>{{cite journal|last=Davies|first=H. A.|author2=Hull J. B. |title=The formation, structure and crystallization of non-crystalline nickel produced by splat-quenching|journal=Journal of Materials Science|year=1976|volume=11|issue=2|pages=707–717|doi=10.1007/BF00551430|bibcode=1976JMatS..11..215D|s2cid=137403190}}</ref>

==== Amorphous metals ====
{{Main|Amorphous metal}}
[[File:Bulk Metallic Glass Sample.jpg|thumb|Samples of amorphous metal, with millimetre scale|alt=Refer to caption]]
In the past, small batches of [[amorphous metal]]s with high surface area configurations (ribbons, wires, films, etc.) have been produced through the implementation of extremely rapid rates of cooling. Amorphous metal wires have been produced by sputtering molten metal onto a spinning metal disk.<ref name=klement60>{{cite journal | last1=Klement | first1=W. Jr. |last2=Willens |first2=R.H. |last3=Duwez |first3=Pol |doi=10.1038/187869b0 |title=Non-crystalline Structure in Solidified Gold-Silicon Alloys |year=1960 |journal=Nature |volume=187 |issue=4740 |page=869| bibcode=1960Natur.187..869K |s2cid=4203025 }}</ref><ref name=lieb76>{{cite journal |last1=Liebermann |first1=H. |last2=Graham |first2=C. |doi=10.1109/TMAG.1976.1059201 |title=Production of Amorphous Alloy Ribbons and Effects of Apparatus Parameters on Ribbon Dimensions |journal=IEEE Transactions on Magnetics |year=1976 |volume=12 |issue=6 |page=921 |bibcode=1976ITM....12..921L}}</ref>

Several alloys have been produced in layers with thicknesses exceeding 1 millimetre. These are known as bulk metallic glasses (BMG). [[Liquidmetal|Liquidmetal Technologies]] sells several [[zirconium]]-based BMGs.

Batches of amorphous steel have also been produced that demonstrate mechanical properties far exceeding those found in conventional steel alloys.<ref name=ponn04>{{cite journal |last1=Ponnambalam |first1=V. |last2=Poon |first2=S. Joseph |last3=Shiflet |first3=Gary J. |title=Fe-based bulk metallic glasses with diameter thickness larger than one centimeter |journal=Journal of Materials Research |year=2004 |volume=19 |issue=5 |page=1320 |doi=10.1557/JMR.2004.0176 |bibcode=2004JMatR..19.1320P|s2cid=138846816 }}</ref>

Experimental evidence indicates that the system Al-Fe-Si may undergo a ''first-order transition'' to an amorphous form (dubbed "q-glass") on rapid cooling from the melt. [[Transmission electron microscopy]] (TEM) images indicate that q-glass nucleates from the melt as discrete particles with uniform spherical growth in all directions. While [[x-ray diffraction]] reveals the isotropic nature of q-glass, a [[nucleation]] barrier exists implying an interfacial discontinuity (or internal surface) between the glass and melt phases.<ref>{{cite web|url=http://www.metallurgy.nist.gov/techactv2004/TechnicalHighlights.html#glass|title=Metallurgy Division Publications|work=NIST Interagency Report 7127|url-status=live|archive-url=https://web.archive.org/web/20080916063500/http://www.metallurgy.nist.gov/techactv2004/TechnicalHighlights.html#glass|archive-date=16 September 2008}}</ref><ref>{{cite journal |last1=Mendelev |first1=M.I. |last2=Schmalian |first2=J. |last3=Wang |first3=C.Z. |last4=Morris |first4=J.R. |author5=K.M. Ho |doi=10.1103/PhysRevB.74.104206 |bibcode=2006PhRvB..74j4206M |title=Interface Mobility and the Liquid-Glass Transition in a One-Component System |year=2006 |journal=Physical Review B |volume=74 |issue=10|page=104206 |url=https://zenodo.org/record/1233751 }}</ref>

==== Polymers ====
Important [[polymer]] glasses include amorphous and glassy pharmaceutical compounds. These are useful because the solubility of the compound is greatly increased when it is amorphous compared to the same crystalline composition. Many emerging pharmaceuticals are practically insoluble in their crystalline forms.<ref>{{cite web|url=http://www-ics.u-strasbg.fr/etsp//research/glass/field.php|archive-url=https://web.archive.org/web/20160525003628/http://www-ics.u-strasbg.fr/etsp/research/glass/field.php|url-status=dead|title=A main research field: Polymer glasses|archive-date=25 May 2016|website=www-ics.u-strasbg.fr}}</ref> Many polymer [[thermoplastic]]s familiar to everyday use are glasses. For many applications, like [[glass bottles]] or [[eyewear]], polymer glasses ([[acrylic glass]], [[polycarbonate]] or [[polyethylene terephthalate]]) are a lighter alternative to traditional glass.<ref name="Carraher-polymer">{{cite book|url=https://books.google.com/books?id=_izOBgAAQBAJ&q=polymer%20glass%20lighter%20alternative&pg=PA274|title=Introduction to Polymer Chemistry|first=Charles E. Jr.|last=Carraher|year=2012|pages=274|publisher=CRC Press|isbn=978-1-4665-5495-5}}</ref>