Thermally evaporated selenium and tellurium-based thim film glasses were carefully characterized to establish the interdependence between their chemical composition and some physical parameters, such as density and optical energy gap. The effects of different metallic additions and annealing at a temperature below the glass transition temperature T-g on the optical characteristics was explored. The optical energy gap E-opt was found to decrease with the addition of metal, the extent of the diminution dependings on the chemical character of the added metal. (C) 2009 Elsevier B.V. All rights reserved.