CHROMOPHORES WITH STRONG HETEROCYCLIC ACCEPTORS - A POLED POLYMER WITH A LARGE ELECTROOPTIC COEFFICIENT

Syntheses of a series of conjugated donor-acceptor chromophores, based on a strongly electron-withdrawing heterocyclic acceptor, have led to compounds with large second-order optical nonlinearities. Incorporati on of one of these chromophores into polycarbonate at 20 percent weigh t loading yielded, after poling at 150 volts per micrometer, a polymer film with an electro-optic coefficient, r(33), of 55 picometers per v olt at 1.313 micrometers. This value is roughly twice that of lithium niobate. A variant of one of these chromophores exhibited improved the rmal stability as needed for use in polymers with higher glass transit ion temperatures. The chromophore was soluble in common organic solven ts, had a scalar product of the dipole moment, mu, and the molecular f irst hyperpolarizability, beta (corrected for dispersion), of roughly 5000 x 10(-48) electrostatic units, and showed less than 10 percent de composition after heating for 20 minutes in air and at 200 degrees C i n an inert organic solvent.