DIELECTRIC PERMITTIVITY PROPERTIES OF A FULGIDE DYE GUEST-HOST LIQUID-CRYSTAL

被引:28
作者
ALLINSON, H [1 ]
GLEESON, HF [1 ]
机构
[1] UNIV MANCHESTER,SCHUSTER LAB,DEPT PHYS & ASTRON,MANCHESTER M13 9PL,LANCS,ENGLAND
基金
英国工程与自然科学研究理事会;
关键词
D O I
10.1080/02678299508032002
中图分类号
O6 [化学];
学科分类号
0703 ;
摘要
The dielectric permittivity of the nematic liquid crystalline mixture E7, doped with a low concentration of the photochromic material thiophene fulgide, was studied and compared with the properties of the pure E7. Fulgides are a group of thermally stable photochromic materials. On irradiation with ultraviolet light, a ring-closure occurs, giving an isomer which is stable if the dye is kept in the dark. The isomerism induces changes to the steric, dipolar and electronic conjugation properties of the species. A capacitive technique was used to determine the dielectric constants of the fulgide-doped liquid crystalline mixtures. The parallel and perpendicular components of dielectric constant were measured using a single cell, in the latter case in the presence of a magnetic field. Measurements were made on the photochromic system before and after ultraviolet irradiation and a marked variation in the dielectric properties of the mixture was observed. This was shown to be entirely due to the differences in phase transition temperatures between the irradiated and non-irradiated guest-host mixtures.
引用
收藏
页码:421 / 425
页数:5
相关论文
共 15 条
  • [1] PHYSICAL-PROPERTIES OF MIXTURES OF LOW MOLAR-MASS NEMATIC LIQUID-CRYSTALS WITH PHOTOCHROMIC FULGIDE GUEST DYES
    ALLINSON, H
    GLEESON, HF
    [J]. LIQUID CRYSTALS, 1993, 14 (05) : 1469 - 1478
  • [2] ALLINSON H, 1993, ANN BRIT LIQUID CRYS
  • [3] ALLINSON H, 1994, THESIS MANCHESTER U
  • [4] Brown GH, 1971, TECHNIQUES CHEM, VIII
  • [5] MEASUREMENT OF THE PERMITTIVITY OF NEMATIC LIQUID-CRYSTALS IN MAGNETIC AND ELECTRIC-FIELDS USING EXTRAPOLATION PROCEDURES
    CLARK, MG
    RAYNES, EP
    SMITH, RA
    TOUGH, RJA
    [J]. JOURNAL OF PHYSICS D-APPLIED PHYSICS, 1980, 13 (11) : 2151 - 2164
  • [6] Durr H., 1990, PHOTOCHROMISM MOL SY
  • [7] PHOTOCHROMIC HETEROCYCLIC FULGIDES .4. THE THERMAL AND PHOTOCHEMICAL-REACTIONS OF "(E)-ISOPROPYLIDENE-[ALPHA-(2-THENYL AND -(3-THIENYL)ETHYLIDENE]SUCCINIC ANHYDRIDES AND RELATED-COMPOUNDS
    GLAZE, AP
    HARRIS, SA
    HELLER, HG
    JOHNCOCK, W
    OLIVER, SN
    STRYDOM, PJ
    WHITTALL, J
    [J]. JOURNAL OF THE CHEMICAL SOCIETY-PERKIN TRANSACTIONS 1, 1985, (05): : 957 - 961
  • [8] TEMPERATURE-DEPENDENCE OF THE ANISOTROPY OF TURBIDITY AND ELASTIC-CONSTANTS OF NEMATIC LIQUID-CRYSTAL MIXTURE E7
    HAKEMI, H
    JAGODZINSKI, EF
    DUPRE, DB
    [J]. MOLECULAR CRYSTALS AND LIQUID CRYSTALS, 1983, 91 (1-2): : 129 - 136
  • [9] KHAN N, COMMUNICATION
  • [10] KURIHARA S, 1988, JPN J APPL PHYS, V10, pL1791