Response Time Characteristics and Holographic Gratings in an Azo-Dye Doped Photorefractive Polymeric Composite

Theoretical and experimental investigation on the applied electric field- and intensity-dependent photorefractive response in a photorefractive polymeric composite is presented. The decay time constant and the corresponding grating-amplitude for the composite consisting of 1-n-butoxy1-2,5-dimethy1-4-(4 ’- nitrophenylazo) benzene : poly(N-vinylcarbazole) : 2,4,7-trinitro-9-fluorenone with a weight ratio 44:55:1 were measured. The results revealed that there existed two gratings simultaneously, one was caused by the photorefractive effect, and the other was contributed from the photo-isomerization process. The dynamic process for the photorefractive grating was explained with a modified band transport model.