Novel cross-linked chromophores based on Diels–Alder or Huisgen reactions

Abstract

To synthesize binary crosslinked materials with high electro-optic coefficients and long term alignment stability, a reaction was developed. Consequently, a series of binary crosslinked materials (WLD1–4) and a single component crosslinked material (WLD5) were fabricated using traditional aniline as the donor. The crosslinking reaction that occurred after the completion of molecular poling orientation converted small molecules into polymer materials, which greatly improved the glass transition temperature and stability of the materials. The high density of chromophores (5.55–6.01 × 10²⁰ molecules per cm³) and first-order hyperpolarization resulted in a large electro-optic coefficient up to 190–237 pm V⁻¹ at 1310 nm. The glass transition temperature of the material increased from 51–75 °C to 117–144 °C after crosslinking. We also tested the long-term stability of the crosslinked material at high temperatures. Results indicated that after heating at 85 °C for over 500 h, more than 85% of the initial r₃₃ value (the electro-optic coefficient) was maintained for the poled and crosslinked electro-optic film WLD5. These structures could further expand the design concept of pure chromophore crosslinked materials and lay a solid foundation for commercial organic electro-optic materials.