Formation and properties of alkali scandium silicate glasses

Alkali scandium silicate glasses containing 25 mol% alkali oxide can be formed containing a maximum of approximate to 15 mol% Sc2O3. The maximum concentration of Sc2O3 which can be added to the base glass dea eases slightly for glasses containing rubidium or caesium. Addition of scandium oxide to the base glasses increases their density, refractive index and glass transformation temperature. Glass transformation temperatures approach 800 degrees C for glasses containing >10 mol% Sc2O3. Although replacement of SiO2 by Sc2O3 always decreases the electrical conductivity the effect of Sc2O3 on the conductivity increases as the atomic number of the alkali present increases. Results of this study indicate that scandium ions increase the connectivity of the vitreous network.