Glasses Technology

Silicon oxycarbide glasses have been synthesized by inert atmosphere pyrolysis at 1000 degree C of gel precursors obtained by cohydrolysis of triethoxysilane, HSi(OEt)//3, and methyl-diethoxysilane, HMeSi(OEt)//2. (more…)

Group ? tris(glycolato)silicates, MSi(OCH//2CH//2O)//3 (where M=Ba, Ca, Mg), can be syntehsized directly by reaction of silica with ethylene glycol and alkaline-earth (group ?) oxides at 200?. These hexa-alkoxy silicates serve as precursors to silicate glass and ceramic powders. They are readily modified by exchange with longer-chain diols into processable polymer precursors. (more…)

Silica glasses doped with small-sized CdS//xSe//1-x crystals were prepared by the sol-gel method. Gels synthesized by the hydrolysis of Si(OC//2H//5)//4, in the presence of CdSeO//4 with NH//4SCN dissolved in HNO//3 or NH//4OH, were heatedin H//2-N//2 atmosphere. The pH value of solutions for CdSeO//4 and NH//4SCN primarily determined the fraction of anions in CdS//xSe//1-x crystals. The anion content in crystals was dependent on the pH value of the solvent and/or heat-treatment temperature, and the sulfur fraction changed from 0.1 to 0.6. The optical absorption spectra were red-shifted as the selenium content and the crystal sizeincreased, and the emission spectra showed a sharp band near (more…)

What is claimed is:

1. A semiconducting glass composition consisting essentially of as given in weight percent:

with V.sub.2 O.sub.5 + MoO.sub.3 + P.sub.2 O.sub.5 being in the range of 70 to 90 weight percent, the glass being chemically stable and having a resistivity within the range of from about 2 .times. 10.sup.7 to about 6 .times. 10.sup.8 ohm.sup.. cm. (more…)

Potassium borosilicate glasses were prepared in families having the general formula of RK//2O·B//2O//3·NSiO//2, where R is the ratio of potassium oxide to boron oxide and N is the ratio of silicon dioxide to boron oxide. The glasses wereprepared for values of R ranging from 0 to 7.0 in the families N=0.5, 1.0, 2.0,and 4.0. ^29Si MAS-NMR measurements (more…)

The dynamic fatigue characteristics of silica glasses with fictive temperaturesof 1000°, 1100°, and 1300? and sodalime glasses with fictive temperatures of470° and 530? were measured in air. For both glasses, samples with higher fictive temperatures had a greater fatigue resistance. Inert strength of silica glasses with fictive temperature of 1000° and 1300? was also measured at liquid nitrogen temperature. Glass with higher fictive temperature had a greater inert strength.

Li, Hong.?Agarwal, Anand.?

United States Patent 3,950,176 Deeg , et al. April 13, 1976
Chemically stable, semiconducting glasses having a resistivity of from about 2 .times. 10.sup.7 to about 6 .times. 10.sup.8 ohm.sup.. cm contain 25 to 35 weight percent of vanadium pentoxide, 10 to 20 weight percent phosphorous pentoxide, and from 35 to 45 weight percent of molybdenum trioxide. These semiconducting glasses are melted readily, are castable into desired shapes, and offer good resistance to devitrification.

XPS O1s spectra were recorded for glasses in the binary PbO-Ga//2O//3 and ternary PbO-Bi//2O//3-Ga//2O//3 systems. Large shoulders with chemical shifts of 1.4 to 1.9 eV were observed in the O1s spectra recorded from PbO-Ga//2O//3 glasses. These shoulders were attributed to the presence of nonbridging oxygens in the structure. The shoulders indicated that, contrary to previous results, PbO was a network modifier as well as a charge compensator and network former. The additionof Bi//2O//3 reduced the number of nonbridging oxygens and, therefore, it was classified as an intermediate. Ga//2O//3 seemed to form GaO//4^- tetahedra, constituting the backbone of the network strcture. Glasses in the PbO-Bi//2O//3-Ga//2O//3 system had their IR cutoff edges located at 7?m with glass transition temperatures in the range of 320° to 400?.

Heo, Jong.?Kim, Choon Gon.?

Judd-Ofelt parameters ?//t with t=2,4,5 for the rare-earth ions Pr^3+, Nd^3+, Sm^3+, Tb^3+, Dy^3+, Ho^3+, Er^3+, and Tm^3+ in alkali and/or alkaline-earth silicate, borate, and phosphate glasses have been determined. The variations of ?//t with the number of 4f electrons of the rare-earth ions are demonstrated, and factors affecting the Judd-Ofelt parameter ?//6 are discussed. (more…)