DIELECTRIC BEHAVIOR OF POLYCARBONATE

The dielectric constant and the dielectric loss of polycarbonate are i nvestigated in the frequency range 30-10(5) Hz and at temperature from 297 to 365 K. The frequency dependence of the impedance spectra plott ed in the complex plane shows semicircles. The system could be represe nted by an equivalent circuit of a bulk resistance in series with a pa rallel surface resistance-capacitance combination. The Cole-Cole diagr ams have been used to determine the molecular relaxation time tau. The temperature dependence of tau is expressed by a thermally activated p rocess. Analysis of the AC conductivity reveals semiconducting feature s based predominantly on a hopping mechanism.