SPECTROSCOPIC ANALYSIS OF ELECTRICALLY POLARIZED POLYACRYLONITRILE.

Electrically polarized and unpolarized films of polyacrylonitrile (PAN) have been investigated by both infrared attenuated total reflection (ATR) and thermally stimulated discharge (TSD). ATR analysis of PAN films has been aimed at explaining the molecular origin of thermally stimulated currents, and consequently that of phenomena contributing to electrical polarization in this material. Preferred orientation of nitrile dipoles along the thickness direction (applied electric field direction) has been detected by ATR in both polarized and unpolarized films. It is suggested that dipolar alignment in unpolarized solvent-cast films could result from internal electric fields associated with space charges. PAN films polarized by high-intensity electric fields (5 multiplied by 10**5 V cm** minus **1, as opposed to 5 multiplied by 10**4 V cm** minus **1) are found to retain orientational anisotropy above 100 degree C, and this is believed to be associated with a structural rearrangement induced by electrical polarization.