A novel polymer PAPE．containing electron donator-acceptor azobenzene chromophores in the main chain

has been synthesized by azo-coupling reaction．The azo polymer was characterized by1H-NMR

UV—Vis spectrometry and thermal analysis．The λmax of the polymer film and DMF solution determined to be 445 nm and 446 nm

respectively．The number average molecular weight determined by GPC was Mn=5600 with a polydispersion index 2．2．The glass transition temperature(Tg)of the polymer was 132℃ observed from DSC thermogram．The results showed the azo polymer can be successfully synthesized through ago—coupling reaction．The synthetic scheme demonstrated in this work is a feasible way to prepare main-chain azo polymers under an extremely mild condition．Dichroism was optically induced in the PAPE films under the irradiation of Ar+ laser beam at 488 nm．and the orientational order parameter obtained was 0．03．Surface—relief-gratings were observed on PAPE films after irradiated by an interference pattern of Ar+ laser beam for 1000s．The surface modulation depth and the grating spacing were measured by AMF to be 89 nm and 900 nm．