THERMOSETTING NONLINEAR OPTICAL POLYMER - POLYURETHANE WITH DISPERSE RED 19 SIDE GROUPS

A new thermosetting second-order nonlinear optical polyurethane polymer with disperse red 19 pendant groups was studied by second-harmonic generation and electro-optic modulation methods. The polymer can be crosslinked by thermal curing during electric field poling. The electro-optic coefficient r13 measured with a Mach-Zehnder interferometer ranged from 5 pm/V at 800 nm to 13 pm/V at 633 nm. The polymer crosslinked during poling showed no significant decay of the nonlinearity at room temperature for thousands of hours. A long-term thermal stability of the dipole alignment at an elevated temperature, 90-degrees-C, was demonstrated. The thermosetting polymer showed improved alignment stability under ultraviolet exposure.