The analysis of the kinetics of stepwise volumetric crystallization of AsSe1.5In0.01 glasses is carried out at temperatures of 200, 220, 240, and 260 degrees C, and of AsSe1.5In0.025, at 240 degrees C, according to measurements of the density of quenched materials using the generalized Kolmogorov-Avrami equation, the results of differential thermal and quantitative X-ray phase analysis, and microscopic observations. A significant acceleration of the bulk heterogeneous nucleation of the lamellar crystals of the main As2Se3 phase of the primary microphase In2Se3, which is released evenly over the entire volume of monolithic glass during isothermal crystallization in the range of 200 to 260 degrees C, is established. The parameters of electrical conductivity and microhardness of quenched semiconductor glass-ceramics (sitalls) at various stages of heat treatment are studied.