Аннотация:The kinetics of stepwise transformations during bulk isothermal crystallization of semiconductor glasses AsSe1.5Snx ( x=0.13, 0.20, 0.28) in the temperature range 210-310 0C has been investigated by the methods of 119Sn NAGRS, XRD, density and microhardness measurements of quenched samples. The analysis of the kinetics of bulk bulk crystallization of glasses was performed according to densitometry data using the Kolmogorov-Avrami equation generalized to stepwise and incomplete isothermal transformations.