Camphor and nopinone derivatives as new photosensitive chiral dopants

E-Z photoisomerizable chiral dopants are a class of materials that can be u sed to prepare birefringent optical components with patterned optical prope rties. Two new photoisomerizable chiral dopants have been synthesized and a nalysed. The materials were derived from nopinone and camphor. The properti es of these compounds were compared with the properties of the methene deri vative described in. earlier publications. The E-isomers of the nopinone an d camphor derivatives had helical twisting powers of 2.7 and 1.7 mu m(-1), respectively. This is a factor of about 10 lower than the value obtained fo r the menthone derivative (-19 mu m(-1)). Due to the high absorption of the Z-isomers relative to the E-isomers of the nopinone and camphor derivative s, isomerization during 365 nm UV exposure proceeded to a much lesser exten t than the isomerization of the menthone derivative. At shorter wavelengths , the absorption of the Z-isomer is much lower than that of the E-isomer an d much higher degrees of conversion could be achieved.