Mixed-alkali effect in alkali borate glasses

The spectral absorption of Cu²⁺ and Ni²⁺, the density, molar volume, refractive index, molar refraction, thermal expansion coefficient, transformation and dilatometric softening temperatures of mixed alkali borate glasses are reviewed. These results indicate that in borate glasses, mixed alkalis do not produce gross alterations of the glass network, and that the weak deviations observed may be related to the boric oxide anomaly.