The paper describes results of a study of glasses of the type Cux (AsSe1.4 I0.2 )100–x for x =0, l, 5, 10, 15, 20 and 25 at% Cu, by the methods of thermomechanical analysis. Values of the thermal coefficients of linear
expansion in solid and visco-plastic phase were determined and the dependence of this parameter on copper concentration was
established. The experimental method used enabled the determination of characteristics glass transition temperature and the
temperature of the beginning of deformation, and it was found that these parameters increase with increase in the copper content.