Inorganic filled poly(2-hydroxyethyl methacrylate) composites have been prepared by gamma irradiation of monomer in the presence of fillers and the thermal properties and stabilities of these systems have been compared. The glass transition temperature (T-g) of the composites was found to be 106 +/- 3 degrees C irrespective of the type of filler and amounts involved. The activation energy of thermal degradation reactions of the composites was found to change depending on the type of filler and increasing volume fraction of poly(2-hydroxyethyl methacrylate). (C) 1998 Elsevier Science Limited. All rights reserved.