Abstract: By using ESR and grafting of styrene onto the irradiated films, the decay of free radicals in films of polytrifluorochloroethylene, copolymers of tetrafiuoroethylene withhexafluoropropylene, and copolymers of tetrafiuoroethylene and ethylene irradiated with fast, electrons was investigated. It is found that in irradiated polytrifluorochloroethylene with a dose 3.5×105 rads, the concentration of free radicals is 6.2×1017 e/g after placed at room temperature for 763 days, percentage grafting of styrene is 21.4-23.9%. The concentration of free radicals in irradiated copolymer of tetrafiuoroethylene and hexafluoropropylene with a dose 5.6×106 rads is 1.0×1018 e/g, percentage grafting of styrene is 32.8 % when placed at room temperature for 888 days. The concentration of free radicals in the film of irradiated copolymer of tetrafiuoroethylene and ethylene with a dose 5.6×106 rads is 0 when placed at room temperature for 591 days. It can be seen that the free radicals formed in irradiated perfluoro or perfluorochloropolymers have a long life, which become shorter when the fluoropolymers contain more hydrogen atoms.