We describe calorimetric and optical studies on the mesophases of 1,4 " (p-terphenyl)-bis[2,3,4-tri(dodecyloxy)benzal]imine. Differential Scanning calorimetric curves reveal that there is a second, much weaker transition just below the usual isotropic-nematic point, Optical observations show that these transitions represent the isotropic-uniaxial nematic transition and at a slightly lower temperature the uniaxial-biaxial nematic transition. We present measurements of the temperature variation of the biaxial angle in the biaxial nematic phase. [References: 15]
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