Second order non-linear optical materials based on poly(p-chloromethyl styrene)

The second order non-linear optical (NLO) materials were prepared based on poly(p-chloromethyl styrene) (PCMS). Two kinds of NLO chromophores, i.e. azo dye Disperse Red 1 (4-[N-ethyl-N-(2-hydroxy-ethyl)-amino]-4′-nitroazobenzene) and 4-hydroxy-4′nitrostilbene, were introduced to the poly(p-chloromethyl styrene) by etherification. On the other hand, the acrylates and methacrylates of these two kinds of chromophores were co-polymerzed with methyl methacrylate (MMA) with PCMS as an initiator by atom transfer radical polymerization (ATRP). The obtained polymers were characterized by GPC, DSC and second-harmonic generation (SHG) measurement. The SHG signals began to decline at temperatures above their T_g's which might result from their branched structures.