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Abstract

Dielectric constant and loss of poly(vinyl alcohol) films of different stereoregularity and crystallinity are measured at frequencies from 30 cps to 3 Mcps in the temperature range from −50 to 25°C. The relaxation strength of local mode relaxation is higher for atactic and syndiotactic samples than for isotactic samples when compared at zero crystallinity. This behavior is reasonably explained in terms of interchain hydrogen bonds in the former and intrachain hydrogen bonds in the latter. Dielectric constant and loss of the crystal aggregate of atactic poly(vinyl alcohol) are measured at temperatures from −50 to 140°C. The relaxation strength of the crystalline relaxation is in good agreement with the theory in which the relaxation is attributed to torsional vibration of crystalline chains. The weak loss peak at low temperatures which almost agrees with the local mode relaxation of bulk samples in the frequency-temperature position is ascribed to the surface disorder of single crystals.