Silica glass from

At room temperatures, crystalline quartz is thermod3mamically more stable than silica glass. From ancient times, humans have converted quartz to silica... 

Figure 4.49 Activation energy for diffusion as a function of atomic radius of diffusing species in silica glass. From W. D. Kingery, H. K. Bowen, and D. R. Uhlmann, Introduction to Ceramics. Copyright 1976 by John WUey Sons, Inc. This material is used by permission of John Wiley Sons, Inc.

Spencer, L. f. Meteoric iron and silica-glass from the meteoric craters of Henbury (Central Australia) and Wabar (Arabia). Min. Mag. XXIII, No. 142, 387-404 (1933). 

Silica glasses from Heraeus were implanted with Cu ions at 50 keV, to a dose of S.OxlO ion/cm at a beam current density of 10 pA/cm. A crucial condition of the implants is that they are thermally bonded to a water cooled sample holder and maintained at a constant substrate temperature of 20°C during the implantation. 

Rabinovich E.M., Johnson D.W. Jr., MacChesney J.B., Vogel E.M. Preparation ofhigh-silica glasses from colloidal gels I Preparation for sintering and properties of sintered glasses. J. Amo-. Ceramic Soc. 1983 66(10) 683-688... 

Fig. 4.6 VDOS of silica glass from a Huang and Kieffer s charge-transfer three-body potential, b Neutron scattering experiments [65]...

Cord in soda-lime-silica glass. (From W. D. Kingery et al.. Introduction to Ceramics, 2nd Edn., John Wiley, New York, 1976, pp. 783-812.)... 

J. Du, L. Rene Corrales, K. Tsemekhman and E. J. Bylaska. Electron, hole and exciton self-trapping in germanium doped silica glass from DPT calculations with self-interaction correction. Nucl. Instrum. Methods Phys. Res. B 255, 2007, 188. 

Fig. XVII-29. Nitrogen isotherms the volume adsorbed is plotted on an arbitrary scale. The upper scale shows pore radii corresponding to various relative pressures. Samples A, Oulton catalyst B, bone char number 452 C, activated charcoal F, Alumina catalyst F12 G, porous glass S, silica aerogel. (From Ref. 196).

Figure Bl.20.8. DLVO-type forces measured between two silica glass surfaces in aqueous solutions of NaCl at various concentrations. The inset shows the same data in the short-range regime up to D = 10 mn. The repulsive deviation at short range (<2 nm) is due to a monotonic solvation force, which seems not to depend on the salt concentration. Oscillatory surface forces are not observed. With pemiission from [73].

Vitreous silica (silica glass) is essentially a supercooled Hquid formed by fusion and subsequent cooling of crystalline silica. It is found ia nature ia fulgerites, ie, fused bodies resulting from lightning striking quart2 sand. 

The purity of 1 and 2 is assessed by analytical gas-liquid chromatography (GC) on a Hewlett-Packard 5890 gas chromatograph equipped with a flame-ionization detector and fitted with a 50 m x 0.2 mm HP-5 fused silica glass capillary column using linear temperature programming from an initial temperature of 150°C for 5 min to a final temperature of 200°C for 10 min at a rate of 5°C/min. 

Glass is composed mainly of silica, Si02, with various oxides added to change the properties. The property differences are substantial, and different amounts of added oxide compounds produce glasses with very different applications derived from these properties. Often the added material is B203 and the products are called borosilicate glasses. From standard... 

For the hard borosilicate glasses and the soda-lime-silica glasses this if around 0-0025 cal °C" cm sec. For vitreous silica (Vitreosil) in the transparent form it is 0-0025 up to 500°C, and 0-0035 from 500 to 1000°C for the translucent form it is 0-0033. 

Figure 4 The structure of the two forms of silica cristobalite (crystalline, left) and silica glass (amorphous, right). (Reprinted with permission from Ref. 4.)...

It seems that sometime during the third millennium b.c.e., somewhere in the Middle East, it was discovered that when a mixture of silica sand and soda is heated to relatively high temperatures, the mixture fuses to form glass. Few other human-made materials are derived, as is glass, from such common and abundant raw materials. Its remarkable physical and chemical properties made glass, already in antiquity, one of the most useful and ubiquitous materials in many areas of the world. 

Kirkbir F., Chaudhuri R., Optical fibers from sol-gel-derived germania-silica glasses, SPIE Proc. 1758, 160-172, (1992). 

J.D. Badjic and N.M. Kostic, Unexpected interactions between sol-gel silica glass and guest molecules. Extraction of aromatic hydrocarbons into polar silica from hydrophobic solvents. J. Phy. Chem. B 4, 11081-11087 (2000)... 

---