The kinetics of crystallization of a glass with composition 30Si02.24.14P205.28.61Ca0.17.25Mg0 (wt%) was studied with variable temperature, by differential thermal analysis. These results were interpreted according to revised theoretical models which describe the dependence of fraction crystallized on temperatures and on the heating rate, and the dependence of the peak temperature on the rate of change in temperature. These models emphasize the differences in crystallization behaviour between "as-prepared" glass samples, and the corresponding previously nucleated samples. The differences in behaviour suggest that the kinetics of crystallization comprise a nucleation stage at temperatures of around 730 deg C, and particle growth for temperatures higher than 800 deg C.
