Effect Of Alkali Ions On The Crystallization Of 3Ba0.5Si02 Glass

This study has investigated the effects of alkali additions on the spherulitic crystallization process in a3Ba0.5Si02 glass. Both Li+ and Na+ increased the growth rate of the spherulites and reduced the crystallization temperature from that in the base glass. Li+ and Na+ also reduced the temperature at which the microstructural transformation from spherulites to laths took place. Dielectric loss measurements suggest that the effect of the alkali additions on crystallization temperature is due to their concentration in grain boundaries, thereby lowering the viscosity of the remaining glass, and increasing mobility rates.