Some characteristics of glass in the Al2O3---B2O3---SiO2 system from the gel

The colorless and transparent glasses in the Al₂O₃---B₂O₃---SiO₃ system with high B₂O₃ and SiO₂ content were prepared from gels at low temperature. Their IR spectra not only revealed the evolution of the gel to glass conversion, but also showed that the formation of mixed bonds in the glasses obtained did not show any effect due to the B₂O₃ content. The accuracy of the glass composition is dependent upon the SiO₂/B₂O₃ molar ratio. The higher the ratio, the less the deviation of the analyzed compositions of the resulting glasses from their original calculated values. It is obvious that the higher the ratio, the lower the thermal expansion coefficient and the higher the transformation temperature of the glass, and the temperature at which the thermal contraction reaches an equilibrium is higher.