Modification of the trap density of the photorefractive polymer compositepoly(N-vinyl carbazole)(PVK),2,4,7-trinitro-9-fluorenone(TNF) andN,N-diethyl-para-nitroaniline(EPNA) was achieved with the addition of4-(diethylamino)benzaldehyde diphenylhydrazone(DEH). Measurements of the response time, the phase shift and the amplitude of the photorefractive grating are presented. ©1995 American Institute of Physics.