The molecular and supramolecular engineering of polymeric electro-optic materials

A new class of electro-optic chromophores, of which 2-dicyanomethylen-3-cya no-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 chromopho re molecules are exceptional. Strong intermolecular electrostatic interacti ons inhibit the efficient poling of these molecules. A statistical mechanic al theoretical treatment is used to quantitatively predict the competition of poling, intermolecular electrostatic interactions, and thermal effects i n defining achievable acentric order and hence macroscopic optical nonlinea rity. Theory is used to predict the optimum chromophore structure and mater ial composition (chromophore loading in a polymer matrix) for maximum elect ro-optic activity and minimum optical loss. Problems associated with lattic e hardening to lock-in poling-induced order are discussed briefly. (C) 1999 Elsevier Science B.V. All rights reserved.