The molecular and supramolecular engineering of polymeric electro-optic materials

A new class of electro-optic chromophores, of which 2-dicyanomethylen-3-cyano-4-(2-[E-(4-N, N-di(2-acetoxyethyl)amino)-phenylene-(3,3-dibutyl)thien-5]-E-vinyl}-5,5-dimethyl-2,5-dihydrofuran (denoted FTC) is the prototype, has been prepared, characterized, and used to fabricate electro-optic devices. The molecular hyperpolarizability and thermal stability of these chromophore molecules are exceptional. Strong intermolecular electrostatic interactions inhibit the efficient poling of these molecules. A statistical mechanical theoretical treatment is used to quantitatively predict the competition of poling, intermolecular electrostatic interactions, and thermal effects in defining achievable acentric order and hence macroscopic optical nonlinearity. Theory is used to predict the optimum chromophore structure and material composition (chromophore loading in a polymer matrix) for maximum electro-optic activity and minimum optical loss. Problems associated with lattice hardening to lock-in poling-induced order are discussed briefly. (C) 1999 Elsevier Science B.V. All rights reserved.