EFFECT OF SIDE-CHAIN STRUCTURE ON THE THIRD-ORDER NONLINEAR OPTICAL PROPERTIES OF ACRYLATE POLYMERS

A serials of acrylate monomers containing long conjugated azobenzene groups were prepared and polymerized in N, N-dimethylformamide (DMA) using 2,2′-azobis(isobutyronitrile) (AIBN) as initiator at 70°C . The monomers and polymers were characterized by FTIR, ¹H-NMR and UV. The molecular weights of polyacrylates were determined by gel permeation chromatography (GPC). The third-order nonlinear optical properties of these polymers were determined by the Z-scan technique with 8 ns pulses at 532 nm, and the relationship between nonlinear optical properties and the molecular structures of substituted chromophores was investigated. The results revealed that all these polymers possessed well nonlinear absorption, and enlarging it-electron conjugated length and strengthening D-π-A push-pull capacity of side-chain chromophores of polymers will effectively enhance the third-order nonlinear optical properties of polymers.