The addition of B2O3 and GeO2 to ZnO-Al2O3-SiO2 glasses decreased the crystallization peak temperature measured by DTA and also decreased the temperature where nucleation rate becomes maximum. ZnAl2Si2O8, Al6Si2O13 and ZnAl2O4 precipitated when ZnO-Al2O3-SiO2 glass crystallizes, and Al6Si2O13 and ZnAl2O4 are transformed to ZnAl2O4. The addition of B2O3 and GeO2 suppressed the precipitation of ZnAl2Si2O8 and Al6Si2O13. The addition of of GeO2 promoted the nucleation of ZnAl2O4.
