Synthesis and electro-optic activities of new side-chain polycarbonates containing nonlinear optical chromophores and isolation groups

Dendritic julolidine-based nonlinear optical (NLO) chromophore (JTCFC) possessing isolation group was designed and synthesized to realize effective isolation of NLO chromophores in the polymer backbone. Electro-optic (EO) polycarbonates (PC-JTCFCs) consisting of the dendritic JTCFC and comonomers were prepared through a facile copolymerization strategy. The sufficiently high polymerizability of the dendritic JTCFC, which could be caused by the well-isolation of chromophores and lack of steric effect, afforded the EO polycarbonates with ultra-high molecular weight (M-w up to 145 990). The DSC analysis showed that the EO polycarbonates exhibited similar T-g values (near 150 degrees C), indicating that the interchromophore interactions are effectively suppressed. The effective isolation of NLO chromophores directly suppressed the dipole-dipole interactions and improved the translation of microscopic hyperpolarizability into macroscopic EO activity. After corona poling, the synthesized EO polycarbonates exhibited a maximum EO coefficient (r(33)) of 55 pm V-1 at 1310 nm, which was greatly enhanced as compared to the guest-host systems reported previously. Moreover, the prepared EO polycarbonates also possessed good temporal stability, 85% of the initial r(33) value of PC-JTCFC-3 could be kept after 500 h at 85 degrees C.