Thin films of amorphous chalcogenide with composition of As33S67 (thickness d=300nm) and silver film (thickness d=30nm) on top of chalcogenide film were deposited by vacuum thermal evaporation. Prepared bilayer Ag/As33S67 was illuminated and photo-induced dissolution and diffusion (OIDD) process of silver in chalcogenide film studied by means of photocalorimetry. The heat flow connected with OIDD process during light exposure as a function of light energy, light intensity and temperature has been studied by means of photocalorimetry. The enthalpies of OIDD process were obtained and attributed to the bond energies of the formed bonds. (c) 2005 Elsevier B.V. All rights reserved.