The decrease of the deterioration-induced second peak height was observed under the presence of a large forward current, not a diffusion current but an excess current, with sweep at audio frequencies at low temperatures. Two independent relaxation processes were found. One of them was a thermal process and had a relaxation frequency with an activation energy of 0.4 eV and an attempt frequency of 1013 cps. The second process which was observable only at temperatures below 170°K was not a thermally activated one and had an almost constant relaxation frequency of about 50 cps. The former process was accompanied by hysteresis while the latter was not. The analysis of the processes by the proposed energy model in this study was only partly successful in interpreting the experimental observations.