Electroabsorption spectroscopy of distyrylbenzene derivatives

We have studied the linear and nonlinear optical properties of model oligom ers based on trans, trans'-distyrylbenzene to investigate the effects of ch emical modification on the electronic structure of stilbenoid oligomers and polymers. Replacing the central para-phenylene ring with a meta-phenylene ring reduces the conjugation of the molecule and introduces disorder into t he film, which significantly reduces Davydov splitting of the main absorpti on band. Alkoxy substitution of any of the phenylene rings red shifts the l owest energy absorption band and enhances the oscillator strength of a high -energy sideband. Absorption by aggregates, which is obscured by effects of scattering on the absorption spectrum, is clearly revealed by electroabsor ption spectroscopy. (C) 2000 Published by Elsevier Science B.V. All rights reserved.