title: Coexistence of polar and nonpolar domains and their photocontrol in the B7 phase of a bent-core liquid crystal containing azo dyes.
abstract: Coexisting polar and nonpolar domains have been studied by means of texture observation, x-ray analysis, optical second-harmonic generation (SHG), and SHG microscopy in the B7 phase of a bent-core mesogen doped with azo dyes. The bent-core molecules take a planar orientation and show high birefringence in the polar domain, while they take a homeotropic orientation and show low birefringence in the nonpolar domain. Good correspondence between real and SHG images was observed under a SHG microscope; the bright (high-birefringent) domain is SHG active and the dark (low-birefringent) domain is not SHG active. Photoisomerization of the azo dyes causes layer reorientation from the layer perpendicular to the substrate to that parallel to it.
authors.affiliation: Department of Physics, Korea University, Seoul 136, Korea.
authors.forename: Heekyung
authors.initials: H
authors.lastname: Kim
authors.forename: Tong Kun
authors.initials: TK
authors.lastname: Lim
authors.forename: Sung Tae
authors.initials: ST
authors.lastname: Shin
authors.forename: Chong Kwang
authors.initials: CK
authors.lastname: Lee
authors.forename: Fumito
authors.initials: F
authors.lastname: Araoka
authors.forename: Masato
authors.initials: M
authors.lastname: Ofuji
authors.forename: Yoichi
authors.initials: Y
authors.lastname: Takanishi
authors.forename: Hideo
authors.initials: H
authors.lastname: Takezoe