Acrylonitrile (AN)-methyl acrylate (MA), acrylonitrile (AN)-ethyl acrylate (EA), acrylonitrile (AN)-butyl acrylate (BA) copolymers with and without doping with ferric chloride were prepared by free radical polymerization at 70°C. Mössbauer spectrum shows no reduction of ferric species to ferrous during the copolymerization. TGA studies show that the addition of ferric chloride changes the thermal decomposition pattern of the copolymer. TGA analysis shows that the inclusion of ferric chloride stabilizes the copolymers by 20–25°C. Mössbauer studies of the copolymers heated at 300°C and 500°C for 15 min showed that during the thermal degration, Fe3+ species was reduced to Fe2+ and then finally it formed -Fe2O3.