Second-Order Nonlinear Optical Polymers with Large NLO Effect and High Thermostability

For organic second-order nonlinear optical (NLO) materials, the universal “nonlinearity-stability” trade-off usually hinders their commercial applications for unbalanced electro-optic properties. Herein, through the incorporation of alkoxy chains as the efficient strategy to facilitate the molecular rotations under the electronic poling process, as well as the fixed network by D-A reactions with the matched temperatures at the optimized molecular orientations of chromophores, the cross-linked polymer films possess significantly improved T_80% value of 113 °C, higher than that of the uncross-linked film by 20 °C, and achieve large d₃₃ value of 125 pm V⁻¹. This design strategy realizes the win-win of second-order NLO effect and thermostability, opening up a new avenue for the development of electro-optic materials with excellent comprehensive properties.