title: Photoinduced circular anisotropy in a photochromic W-shaped-molecule-doped polymeric liquid crystal film.
abstract: Photoinduced circular anisotropy has been demonstrated in thin films of a main-chain polymeric liquid crystal (PLC) system doped with photochromic W-shaped molecules containing two azobenzene groups by irradiating with circularly polarized light (CPL). Reversible photoinduced circular dichroism (CD) was observed with sign relevant to the handedness of the CPL. The experimentally observed CD spectra were analyzed using the DeVoe polarizability model associated with the coupled oscillator method. We also propose a mechanism for the photoinduced circular anisotropy in our system; nucleating the W-shaped molecules with preferential twisted conformation by CPL irradiation, and triggering the local formation of a chiral structure in the W-shaped-molecule-doped main-chain PLC medium.
authors.affiliation: Department of Organic & Polymeric Materials, Tokyo Institute of Technology, O-okayama, Meguro-ku, Tokyo 152-8552, Japan.
authors.forename: Suk-Won
authors.initials: SW
authors.lastname: Choi
authors.forename: N Y
authors.initials: NY
authors.lastname: Ha
authors.forename: Kazuaki
authors.initials: K
authors.lastname: Shiromo
authors.forename: Nandiraju V S
authors.initials: NV
authors.lastname: Rao
authors.forename: Manoj Kr
authors.initials: MK
authors.lastname: Paul
authors.forename: Takehiro
authors.initials: T
authors.lastname: Toyooka
authors.forename: Suzushi
authors.initials: S
authors.lastname: Nishimura
authors.forename: J W
authors.initials: JW
authors.lastname: Wu
authors.forename: Byoungchoo
authors.initials: B
authors.lastname: Park
authors.forename: Yoichi
authors.initials: Y
authors.lastname: Takanishi
authors.forename: Ken
authors.initials: K
authors.lastname: Ishikawa
authors.forename: Hideo
authors.initials: H
authors.lastname: Takezoe