Cross‐linked stable second‐order nonlinear optical polymer by photochemical reaction

A new method for obtaining cross‐linked second‐order nonlinear optical polymer by photochemical reaction has been described. An active dye was processed and poled in a photoreactive polymer in a manner similar to doped polymer system, and photo‐cross‐linked in the poled phase by ultraviolet irradiation. The dye doped (20% by weight) cross‐linked polymer has a nonlinear optical coefficient d33 of 5.1 pm/V at 1.540 μm and shows no relaxation after being subjected to thermal treatment at 60 °C for 0.5 h.