For a quantitative elucidation of damage induced by gamma rays in polytetrafluorethylene (Teflon), we studied its kinetics using 19F nuclear magnetic resonance as a probe. An NMR parameter “ P” was defined to describe a “constant amount of reaction” in terms of changes in the crystallimty of Teflon during irradiation at different dose rates (γ, photons/sec), irradiation time ( t, sec), and temperature ( T, °K). The data were fitted to an equation of the form ln( P − 1) = a( γ, T) + b( γ, T) ln t, where the dose rate and temperature dependence of the coefficients are shown in parentheses. The parameter P = A o A , where A o and A are the amplitudes of the NMR derivative curve for the control (unirradiated) and irradiated samples, respectively. For a given level of “constant damage” (e.g., 33% decrease in P), a characteristic time t c was derived from the equation: l nt c = ( E a RT ) + const., where E a is an experimental activation energy. A computer-aided analysis was used to separate out (a) the “radiation” and (b) “thermal” contributions to the activated processes. The activation energies for a constant damage level were thus calculated to be about (a) 3.4 and (b) −0.041 kcal/mole, respectively. The physical significance of these parameters deduced on the basis of photochemical kinetics has been interpreted at the macro- and microscopic levels of polymer-radiation interactions.