NONLINEAR DIELECTRIC AND CONDUCTIVE SPECTRA OF POLYMERS

Nonlinear complex permittivities have been measured as a function of frequency for various polar polymers by applying a sinusoidal electric field and detecting higher harmonic dielectric responses. It is shown that the Debye relaxation of the linear permittivity accompanies the third-order nonlinear relaxation represented by epsilon3*=DELTAepsilon3/(1+iomegatau3)3 in accord with phenomenological prediction. Combinations of relaxation strengths, DELTAepsilon1 and DELTAepsilon3, allow estimates of the saturation polarization as well as the moment and density of equivalent dipoles comprising the relaxation process. Analogous measurements and analysis have been extended to examine the nonlinear conductive spectra of ion-conducting polymers.