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


X-ray-induced damage in Estane 5703 has been studied by luminescence, optical absorption and electron spin resonance techniques in the temperature interval ≈ 10-300 K. Molecular motion of the polymer soft segment, as determined by viscoelastic measurements, is correlated with features in the glow curve, indicating charge detrapping vs thermal destruction of cavity traps. Spectral emission is characterized by four Lorentzian bands with maxima at 2.34, 2.55, 2.74 and 2.93 eV, which are attributed to triplet-to-singlet (π, π*) electronic transitions of the phenyl group in the polymer hard segment. Absorption peaks at 3.97, 4.29 and 4.46 eV are also assigned to transitions within this group. Several radicals with overlapping resonances are induced at 35 K, which, with increasing temperature, evolve into the relatively stable peroxy free-radical at room temperature.

Publication Title

Nuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms