The effect of light polarization on the photodoping of As2S3films is reported. Provided that the photodoping is performed with linearly polarized light, a large negative photodichroism is induced. If the sample is thermally doped prior to illumination with linearly polarized light, the photodichroism is positive and its value is much smaller. A microscopic model is proposed based on the assumption that linearly polarized light, being absorbed predominantly by glass fragments oriented parallel to the electric vector of the light, can either destroy these fragments or increase their number, which would result in different signs of the photo-induced dichroism.