Analysis of UV Assisted Phase Transitions in Mixtures of Liquid Crystals with Photochromic Compounds by Photopyroelectric Calorimetry
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In this work, an upgraded photopyroelectric setup has been used to investigate phase transitions in liquid crystals dispersed with photochromic molecules. In particular, we have studied the thermal diffusivity before, during, and after the photo-induced conformational changes of the dispersed photochromic molecules. Upon sample irradiation, an opposite shift of the phase transition temperatures were observed in the investigated 8CB–NP and 8CB–7AB mixtures due to the different changes in the shape undergone by the dispersed active molecules.
KeywordsPhase transition Photochromic liquid crystal Photopyroelectric technique
The authors are grateful to Prof. J. Thoen from the University of Leuven, BE and Dr. T. Kosa from the Alpha Micron, Inc., Kent, Ohio, USA for providing the azo-based and the naphtopyran photochromic molecules, respectively.
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