Abstract

Conjugated intramolecular charge transfer systems such as the paranitroaniline derivatives have remained so far one of the most studied classes of organic molecules with enhanced quadratic optical properties. Nevertheless, under the influence of dipole/dipole interactions such molecules are prone to form light scattering aggregates in dilute media or crystallize in centrosymmetric lattices, that results thus in the material having no macroscopic second-order susceptibility. This approach was recently revised, and a new engineering scheme was proposed: octupolar molecules, that can possess large nonlinear optical properties together with good transparency but that do not possess a permanent dipole moment, may circumvent the problem discussed above.^1,2 However, since the absence of dipole moment in such molecules prevents dipolar orientation, no polar order can be expected from standard polarization techniques such as Corona poling.

© 1994 IEEE