Characterization of azobenzene chromophores for reversible optical data storage: molecular quantum calculations

Azobenzene chromophores are promising as molecularly engineered materials f or reversible optical data storage based on molecular reorientation. In thi s paper, the optical properties of several different azobenzene chromophore s are studied using molecular quantum calculations. Special emphasis is put on molecular anisotropy since a high degree of anisotropy is essential for the storage performance. The trans isomers are all found to be practically one-dimensional whereas the anisotropy of the cis isomers is highly depend ent on substituents. Molecular reorientation of chromophores in liquid-crys talline polymers is simulated in order to study the influence of lacking ci s anisotropy. It is demonstrated that photoinduced birefringence is signifi cantly reduced in materials characterized by a low degree of cis anisotropy .