Nucleation and crystallization of Na2O-2CaO-3SiO2 glass by differential thermal analysis

DTA is presently used to characterize the nucleation and crystallization processes of the Na2O-2CaO-3SiO2 glass. A nucleation rate-temperaturelike curve is obtained by plotting either the reciprocal of the temperature corresponding to the crystallization peak maximum, or the height of the crystallization peak, as a function of nucleation temperature. The nucleation-temperature range for this glass composition, 550-650 C, and the maximum nucleation temperature of 600 + or - 5 C, are found to be in excellent agreement with those associated with the classical nucleation technique, followed by isothermal crystallization. It is noted that when most of the nucleation occurs during the DTA measurements, a modified Kissinger equation must be used to calculate the crystallization energy.