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Thermally Stimulated Luminescence and Electron Spin Resonance Study of Gamma Irradiated Poly Carbonate

B. Sanjeeva Rao, M. Papi Reddy, A. Raju, S. Kalahasti, E. Venkateshwar Rao


Polycarbonate (PC) is an industrially important polymer. Gamma irradiation effects of PC are investigated by thermally stimulated luminescence (TSL) and electron spin resonance (ESR) techniques. The TSL spectra of irradiated PC have shown two glow peaks, around 149oC (422 K) and 165oC (438 K). The observed glow peaks are analysed by initial rise methods, Chen’s method and modified initial rise method. The trap parameters corresponding to the two glow peaks and their activation energies are evaluated. A correlation of results between the three methods was observed. The glow peaks are assigned to be due to the release of trap centres facilitated by molecular motion of PC chains around the glass transition region. The trap centres are thought to be created due to the chain cleavages and subsequent reactions occurred due to irradiation of PC. The results are further confirmed by recording ESR spectra of irradiated PC under different conditions.


Polycarbonate, gamma irradiation, TSL glow peaks, activation energy, ESR spectra, free radicals

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