Results on the variation in optical and physicochemical properties of amorphous Ge-S-Ga films under band-gap light exposure have been summarized. Maximal irreversible photoinduced changes in the absorption edge shift, optical energy gap, glass transition temperature, microhardness and selective etching have been observed at compositions with a ratio of S/Ge = 2 and about 10 at.% Ga. The established photobleaching effect is connected with an increase of the local structure ordering and photooxidation.