In the present paper the experimental results on steady-state photoconductivity of amorphous (As₄S₃Se₃)_1-xSn_x and Ge_xAs_xSe_1-2x thin films are presented and discussed. It was shown, that the spectral distribution of the stationary photoconductivity for both glass systems depends on the composition and polarity of the illuminated electrode. The experimental results are discussed in framework of the multiple trapping models for amorphous materials, with exponential distribution of the localized states in the band gap. The contact phenomenon appears at the interface between a metal electrode and an amorphous layer, what also is considered to be responsible for the peculiar features of photoelectric properties of investigated materials.