THERMALLY STIMULATED DEPOLARIZATION CURRENT OF A NONLINEAR-OPTICAL SIDE-CHAIN POLYMER

Thermally stimulated depolarization current (TSDC) of a nonlinear opti cal side chain polymer under various poling conditions is studied to c haracterize the relaxation process in it. To characterize the TSDC of the polymer, a bi-exponential function and an exponential function are used respectively. It is indicated that the TSDC, originated only fro m the alpha- or beta-relaxation process, can be adequately expressed w ith an exponential function for the low-temperature side of the TSDC c urve. For the alpha-process, the results obtained from the TSDC data a re compared to that obtained from both the dielectric spectrum and the rmal degradation behavior. The effect of the space charge on the TSDC data is discussed. Based on the TSDC data, it is got that the relaxati on strength of beta-process is only 3% of that of the alpha-process.