Phase transition temperatures of LCs using Fabry-Perot etalon

A spectroscopic technique using the Fabry-Perot etalon coupled with a spectrometer has been used to determine most accurately the phase transition temperatures of a wide range of liquid crystals viz. nematic, smectic and cholesteric. Using this technique new mesophase transitions have been detected and classified for the cholesteric liquid crystals((13)). These findings have been corroborated by the analysis of the thermal runs of the same samples using Differential Scanning Calorimetery. The technique has been applied successfully to determine the PTTs of FLCs and AFLCs too. A comparison of the results obtained by us with those reported by others clearly indicates the success of the Fabry-Perot technique in determining the PTTS with greater sensitivity.