Luminescence, optical absorption and electron spin resonance of an X-irradiated poly(ester urethane)

X-ray-induced damage in Estane (R) 5703, a segmented poly(ester urethane) c opolymer, has been investigated by thermally stimulated luminescence, radio luminescence, optical absorption and electron spin resonance techniques ove r a wide temperature range. Some glow curve features correlate with molecul ar motion of the polymer, as determined by viscoelastic measurements, indic ating charge detrapping via thermal destruction of cavity traps. Spectral e mission consists of four Lorentzian bands with maxima at 2.38, 2.55, 2.74 a nd 2.93 eV, which are attributed to triplet-to-singlet (pi, pi*) electronic transitions of the phenyl group in the polymer hard segment. Absorption pe aks at 3.97, 4.29 and 4.46 eV are also assigned to (pi, pi*) transitions of the phenyl group. Several radicals with overlapping resonances are induced at low temperature, which, with increasing temperature, evolve into the re latively stable peroxy radical at room temperature. (C) 1999 Elsevier Scien ce Ltd. All rights reserved.