Structural relaxation in a low molecular weight poly(methylphenyl siloxane)
The results of dynamic light scattering, ultrasonic and dielectric measurements of a bulk poly(methylphenyl siloxane) with M W=1800 g/mol over a broad temperature and frequency range are reported. The temperature dependence of the reorientational relaxation times exhibit very fragile behaviour and indicates the decoupling of density and orientational relaxation times at temperatures higher than 1.2T g. This suggests a major contribution of volume structural rearrangements to longitudinal relaxation processes for this sample in the ultrasonic and hypersonic frequency region.
Key wordsReorientational relaxation longitudinal relaxation poly(methylphenyl siloxane)
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