Contribution of germanium dioxide to the thermal expansion characteristics of some borosilicate glasses and their corresponding glass-ceramics

摘要

The thermal expansion characteristic of some lithium aluminium germanium borosilicate glasses and their crystalline solids have been investigated. The base glass composition was modified by partial replacement of germanium dioxide instead of silica. In some cases, however, TiO_2 was also added to some selected glasses as a nucleation catalyst. Slight increase in the thermal expansion coefficient (α) values of the glasses and corresponding slight decrease in both transition (Tg) and softening (TS) temperatures are detected by GeO_2/SiO_2 replacements, however, the reverse results were recorded by TiO_2 addition.