Abstract
The crystallization behavior of Na2O-SiO2 glasses was studied by Differential Thermal Analysis(DTA). The crystallization peak temperature (TC) increased with an increase of SiO2 content. For the quenched glasses, homogeneous nucleation was dominant in the low SiO2 composition, while surface nucleation was dominant in the composition higher than 55mol%SiO2. The heat treatment at the temperatures between 653 and 773K reduced TC due to the nucleation during heat treatment. The decrease of TC corresponds to the increase of the number of nuclei in the glass sample for DTA measurement. The ratio of crystallization peak temperature to liquidus temperature was used to evaluate the thermal stability of glasses. It was found that this parameter was a good linear relationship with the critical cooling rate for glass formation.
