On the application of the KJMA equation on the analysis of isothermal crystallization kinetics

A discussion and recommendation on the determination of the overall activation energy of the isothermal crystallization using the KJMA formalism is presented. The kinetic parameters of crystallization process were determined and compared using the two widely used forms of the KJMA equation: alpha= 1 - exp(-(Kt)(n)) and alpha= 1 - exp(-(k) over dott(n)). Experimental data used for the present analysis was obtained for Sb 1 oSe90 chalcogenide glass using isothermal DSC measurements. The KJMA equation alpha= 1 - exp(- (Kt)(n)) was found to provide more unambiguous estimation of the activation energy. Moreover, more accurate method is used to calculate the activation energy by avoiding the conventional ln(-ln (1-alpha)) vs. 1/T plot that was commonly used for the purpose of estimating the activation energy. A recommendation for a simple method of determination of the activation energy is given. This method is based on the variation of the width at half maximum of the crystallization peak with crystallization temperature of the isothermal measurements.