Sen'i Gakkaishi
Online ISSN : 1884-2259
Print ISSN : 0037-9875
Volume 60, Issue 6
Displaying 1-50 of 54 articles from this issue
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  • Yumei Lu, Fuyuki Hasegawa, Yukie Kawazu, Kenro Totani, Takashi Yamashi ...
    2004 Volume 60 Issue 6 Pages 165-172
    Published: 2004
    Released on J-STAGE: February 15, 2006
    JOURNAL FREE ACCESS
    Three kinds of the two-photon chromophores are used to investigate the process of electron transfer between the initiator and the multifunctional acrylate monomer in two-photon-induced polymerization. Their molecular structures are simplified as D- -d- -D, D- -D and D- -a- -D, where D is the strong donor terminal group, is a -conjugated core, d and a the electron-donating and electron-accepting side group linked with the -conjugated core, respectively. We noticed that the emission of those chromophores is very sensitive to the solvent polarity. Additionally, the red-shift, structureless and long-lived emission was observed in the monomer. Correlated with quantum chemical calculation (MOPAC-PM5), we proposed a process of electron transfer in two-photon-induced polymerization (TPIP). Following the non-irradiation from the high excited state (S2), intramolecular charge transfer (intra-CT) takes place from the terminal group to the core in the primary step, where intra-CT state is named as intra-exciplex. Then the rapid electron hopping from the ion radical core of the chromophore to the monomer was initiated. The electron transfer produces the ion radical pair, attributed to the photopolymerization. Therefore, the rate of two-photon-induced polymerization is determined by an equilibrium of electron transfer and back electron transfer between initiator and monomer to some extent in spite of the contribution of highly sensitivity in two-photon absorption to the number of the excited chromophore.
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  • Hisashi Ogasawara, Kiyotaka Shigehara, Seizo Miyata
    2004 Volume 60 Issue 6 Pages 173-178
    Published: 2004
    Released on J-STAGE: February 15, 2006
    JOURNAL FREE ACCESS
    The five-layer waveguide composed of Langmuir-Blodgett films were prepared from combination of low molecular weight amphiphilic NLO dye, n-Docosyl-4-nitrophenylurea (DONPU) and SHG inactive polymer. The NLO dye was deposited as y-type LB films. The SHG efficiency of this film was dominated by the contribution from in-plane components such as d33. Other tensor components are almost negligible. The second NLO layer was deposited on PDiPF films after reversing the dipping direction to introduce the inversion of the nonlinear susceptibilities across the film. By selecting the proper combination of the SHG inert layer and SHG active layers the mode dispersion curves were compensated to have the same slopes. In fact there are four intersections of the mode dispersion curves, a very good thickness tolerance for phase-matching can be expected. Five-layer organic waveguides prepared by Langmuir-Blodgett techniques exhibit high overlap integral as well as large fabrication tolerance of thickness up to 56 nm. This large fabrication tolerance for phase-matching is 8.6 times larger than that of conventional three layer waveguide.
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  • Toshihiro Koyano, Isamu Akiba
    2004 Volume 60 Issue 6 Pages 179-182
    Published: 2004
    Released on J-STAGE: February 15, 2006
    JOURNAL FREE ACCESS
    Anisotropic light scattering properties of uniaxially oriented polymer blend sheet-polarizers that allow generation and analysis of polarized light were investigated. By proper selection of materials and processing conditions, phase-segregated polymer blends are produced in which the refractive index of the dispersed phase matches the ordinary refractive index perpendicular to the orientation direction of a birefringent continuous phase, while, simultaneously, a large mismatch exists between the refractive indices parallel to that orientation direction. Such films appear transparent or opaque (white), depending on the polarization direction of the incident light. Polarizing efficiency of these blend films found to be about 70% and strongly depends on the shape of phase-segregated domain structure. Rod-shaped domain with large aspect ratio gives high polarizing efficiency.
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