Identification and Utilization of Specific Spatially-Anisotropic Electronic Intermolecular Electrostatic Interactions to Enhance Acentric Order in Organic Electro- Optic Materials

摘要

Electro-optic materials prepared from dipolar organic chromophores require finite noncentrosymmetric (acentric) organization of chromophores for nonzero activity. Such acentric order, , is most commonly introduced by electric field poling of chromophore- containing macromolecular lattices near their glass transition temperature. Anisotropic intermolecular interactions, together with the chromophore dipole-poling field interaction, determine the order that is achieved. The electronic dipolar interactions associated with typically- prolate-ellipsoid-shaped chromophores can strongly attenuate poling- induced order as chromophore loading (concentration) is increased. To offset this undesired effect, the shape of chromophores has been modified to make them more spherical. While exploitation of such nuclear repulsive (steric) interactions has led to some improvement of electro-optic activity, identification of electronic intermolecular electrostatic interactions that can significantly enhance poling-induced order is important to the advancement of the field of organic electro- optics.