3-DIMENSIONAL ORIENTATIONAL CONTROL OF MOLECULES BY SLANTWISE PHOTOIRRADIATION

When a film of poly[2-(4-phenylazophenyloxy)ethyl methacrylate] is sub jected to ii-radiation with nonpolarized 436 nm light for n-pi excita tion at an oblique incident angle with respect to a film surface, dich roism is induced as a result of the reorientation of azobenzene chromo phores. The orientational direction is determined reversibly by an inc ident plane of the light while azobenzene residues reorient in a direc tion parallel with the light propagation. This procedure is applicable to the generation of tilt angles of nematic liquid crystals assisted by obliquely photoirradiated films as a function of exposure doses, ma intaining homogeneous alignment during photoirradiation. (C) 1998 Amer ican Institute of Physics.