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TitleOrientation and solvatochromism of dyes in liquid crystals
Publication TypeJournal Article
Year of Publication2003
AuthorsPålsson, L.-O., Szablewski M., Roberts A., Masutani A., Love G.D., Cross G.H., Bloor D., Kay A.J., Woolhouse A.D., and Yasuda A.
JournalMolecular Crystals and Liquid Crystals
Pagination43/[279] - 53/[289]
Date Published2003
ISSN15421406 (ISSN)
KeywordsAnisotropy, Bathochromic shift, Carrier concentration, Dyes, Electrooptical effects, Guest-host interactions, Hydrogen bonds, Isotropic solvents, Light absorption, Light polarization, Liquid crystals, Molecular orientation, Order parameter, Reduction, Solubility, Solvatochromism, Solvents, Switching
AbstractThe orientation and solvatochromism of some dye molecules in a liquid crystal have been, investigated. Interactions with the host and, the structure of the dye molecule affect the macroscopic alignment of dichroic dye molecules in a liquid crystal. It was observed that some dye molecules show a large bathochromic shift of their absorption maxima in the liquid crystal host relative to the situation in isotropic solvents. It is suggested that this is due to the occurrence of a much weaker reaction field in the anisotropic, rigid host. These dye molecules show little or no apparent order in the anisotropic host despite the observation of a reduction in the electro optic switching time when the dye is present. The highest degree of macroscopic alignment was observed for a merocyanine compound, which showed the smallest solvatochromic shift in the liquid crystal host. These results are discussed in terms of the steric, dipolar and hydrogen bond interactions between the guest and the host.

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