A novel phenomenon of self-enhancement of reflectivity of a self-pumped Phaseconjugator during the time interval in which no light illuminates the conjugstor is observed.The response time of self-pumped phase conjugators of Ce-doped or Mn-doped pottasiumsodium strontium barium niobate (KNSBN) single-domain crystal is shortened obviously byusing an intermittent light. The qualitative explanation about experimental results is givenusing a fundamental charge carrier migration model via the measurement of photovoltaic and pyroelectric fields. Some further experiments have been done to support our analysis. The reduction of conjugation fidelity of the self-pumped phase conjugators is also explained in terms of a photo-induced internal field.