Temperature Function of Birefringence and Structural Changes in Carbazole Crystal |
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Authors: | Włodzimierz J. Kusto Józef W. Rohleder |
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Affiliation: | Institute of Organic and Physical Chemistry, Technical University , Wybrze?e Wyspiańskiego 27, 50-370, Wroc?aw, Poland |
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Abstract: | With a modified quarter-wave Sénarmont compensator, exact measurements of the optical path difference have been carried out in (010) plates of carbazole, C12H9N, in the temperature range 20 < T < 190°C. At a temperature near 155°C distinct anomaly has been found corresponding to crystal-to-crystal phase transformation. The birefringence changes are discussed in terms of temperature dependence of density and orientation of molecules in the unit cell due to thermal expansion of the crystal. |
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Keywords: | geometry of LC-molecules mesogenic central methylene spacer mesogenic cyclohexane derivatives |
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