RELATIONSHIPS BETWEEN THERMOLUMINESCENCE, RADIATION-INDUCED ELECTRON-SPIN RESONANCE AND TRACK ETCHABILITY OF LEXAN POLYCARBONATE

Lexan sheets exposed to 252Cf fission fragments are subjected to TL readout. The surviving tracks are measured, taking the etchable track length as a measure of the residual radiation damage. The decrease in the etchable track length is compared with the variation in TL glow and in ESR signal. The TL and ESR signals are also examined for 60Co gamma-radiation and as functions of dose and post-irradiation time. It is suggested that the etchability of the latent track is associated with molecular fragments produced by chain-scission, and that the recombination of these fragments under heating for TL readout (at 3.6°C sec-1) produces a glow peak at ∼220°C. The ESR signal is shown to be consistent with the presence of free radicalsassociated with the polymer matrix, and is found not to be correlated with the etchability of the latent tracks. A suggestion is made that this signal is associated with the lower-temperature glow peaks in Lexan. © 1979.