Studies on Novel Photoselectable Organic NLO-Molecules

NLO-chromophores of the azobenzene type and of the stilbene type have been used either as dopants or as sidegroups in polymers in order to realize NLO-materials in which the refractive index and the nonlinear susceptibility could be modified optically.1,2 These changes are based on the photochemical transformation of these molecular units from the elongated trans state to the bent cis-state. Since the trans state is the thermodynamically stable state, the cis-isomers generally undergo a thermally activated relaxation back to trans even below the glass transition temperature.3