Effect of Al2O3 on phase separation and crystallization in ZnOAl2O3B2O3SiO2 glasses

Abstract The effect of alumina on the phase separation and the crystallization of the glasses of composition (mol%) 18ZnO·30B 2 O 3 ·52SiO 2 and O-40 Al 2 O 3 was studied using an electron microscope and IR spectroscopy. The main crystalline phase appears in the microphase for which the compositions are not nearer to the crystal stoichiometry than the mean. The addition of Al 2 O 3 suppresses the immiscibility but enhances the crystallizability.