The paper describes the results of a study of glasses of the type CuxAs50Se50-xfor x=5, 10 and 15 at.% Cu, by the method of thermomechanical analysis. Values of the thermal coefficients of linear expansion
in solid (αg) and visco-plastic (αω) phase were determined. On the basis of the results obtained using the mentioned methods it was possible to determine the
specific temperature of the beginning of the softening process of the glass (Tg), as well as the temperature of the beginning of the deformation (Tω). It was shown that coefficients of linear expansion decrease with the increase of Cu content. On the other hand, the increase
of Cu content caused the increase of the temperatures. The analytical forms of dependence of four physical parameters αg, αω, Tg, Tωas a function of the Cu content were fitted.