T. Orlova, I. Terenetskaya
Jun 16, 2011
Molecular Crystals and Liquid Crystals
At the first time a combined method of UV-absorption spectroscopy and Stokes-polarimetry were used for investigations of cholesteric liquid crystals induced by UV-photosensitive steroid provitamin D3 molecules. It is determined that trans-isomer tachysterol is the left-handed chiral dopant in contrary to initial provitamin D3. The measurements of detailed distributions of light polarization ellipticity after passing through planar liquid crystal cells have shown that ellipticity changes are in close agreement with the variations of calculated equilibrium cholesteric pitch. It has been shown that UV-induced changes of cholesteric structure and alignment depend both on the liquid crystal thickness and initial concentration of provitamin D3 dopant.