The effect of a local electric field upon photogeneration efficiency was investigated through analyses of the dependence of photocurrent, photorefractive gain, diffraction efficiency, and birefringence on the applied field of a novel photorefractive polymer containing an ionic tri(bispyridyl) ruthenium complex. It was found that since this polymer system possesses a low glass transition temperature, the dipole moments formed between the counter ions are readily aligned and generate ionic dipole field which screen photogeneration sites from the applied field. This local field lowers the photogeneration efficiency and results in the saturation of photocurrent and photorefractive gain at high applied field. This local field’s effect on an ionic polymer is further confirmed experimentally by comparing the photoconduction of a similar nonionic polymer. ©1998 American Institute of Physics.