Poling Effects on Anisotropic Temperature Changes in NMR Second Moments of Drawn PVDF Films

For the drawn PVDF film, the NMR second moment vs temperature curves at 0° and 90° of the alignment angle (γ) cross over each other during the motional narrowing in the T g rgion (∼-50^° C ). On poling, however, they decrease almost in parallel up to -20^° C and show another narrowing above 30°C depending strongly on γ. These findings indicate that the molecular chain is oriented in the non-crystalline region and the poling more clearly separates low orientations from high orientations. The increase in the high orientation part should be attributed to polarization in the oriented non-crystalline region.