Crosslinkable benzocyclobutene based host polymer for high temporal stability of organic second-order nonlinear optical materials

Abstract

Second-order nonlinear optical (NLO) materials have become a pivotal core for photonic devices with the development of the information globalization. The alignment stability of chromophores is the key factor affecting the services life of materials. Benzocyclobutene (BCB)-based resin, as a good encapsulating materials, exhibited excellent thermal stability after cross-linking reaction. BCB remains a challenge if used directly in NLO materials due to its high curing temperature. Benzocyclobutene (BCB)-based co-polymer have been synthesized and systematically investigated for improving temporal stability of NLO materials, and bismaleimide (BMI) had been introduced as curing agent for further tuning the curing temperature of BCB in this paper. As differential scanning calorimetry (DSC) curves analysis, introduction of curing agent BMI could efficiently improve reactivity of the ring-opening and then cycloaddition of BCB group leading to lower curing temperature (the peak temperature decreased from 194 °C to 160 °C), which prevent the decomposition of doped chromophore during cross-linking. Thermal stimulated depolarization (TSD) results indicated that the temporal stability of NLO materials was remarkably increased due to the cross-linked network structure.