Optical and magnetic resonance measurements of a segmented poly(ester urethane)

X-ray-induced damage in Estane(R)5703 has been studied by luminescence, opt ical absorption and electron spin resonance techniques in the temperature i nterval approximate to 10-300 K. Molecular motion of the polymer soft segme nt, as determined by viscoelastic measurements, is correlated with features in the glow curve, indicating charge detrapping via thermal destruction of cavity traps. Spectral emission is characterized by four Lorentzian bands with maxima at 2.38, 2.55, 2.74 and 2.93 eV, which are attributed to triple t-to-singlet (pi, pi*) electronic transitions of the phenyl group in the po lymer hard segment. Absorption peaks at 3.97, 4.29 and 4.46 eV are also ass igned to transitions within this group. Several radicals with overlapping r esonances are induced at 35 K, which, with increasing temperature, evolve i nto the relatively stable peroxy free-radical at room temperature. (C) 1999 Elsevier Science B.V. All rights reserved.