Based on the results of the differential scanning calorimetry, of transmitted light intensity measurements and of texture observations the phase diagram of 4-(6-heptafluorobutanoiloxyhexyloxy)biphenyl-4'-carboxylate(S)-4-(methyloheptyloxy-1-carbonyl)-phenyl (4H6) was obtained. The following phases were identified on cooling: isotropic, smectic A, smectic C*, smectic C*_{A} phases and a highly ordered phase called SmX and its glass. During heating transformation from glass of SmX to SmX phase and then transition to a metastable Cr2 phase, evolving to the more stable Cr1 phase, were observed. On further heating SmC*_{A}, SmC* and Sm phases were identified. When Cr2 was cooled, a glass transition was also observed.
Basing on the results of differential scanning calorimetry and transmitted light intensity methods and texture observations in the temperature range from - 50C to 90C phase diagram of 1-[3-fluoro-4-(1-methylheptyloxycarbonyl)phenyl]-2-[4'-(2,2,3,3,4,4,4-heptafluorobutoxybutoxy)biphenyl-4-yl]ethane was established. Monotropic system of thermodynamic phases was found. On cooling the isotropic phase transforms at 85C to ferroelectric SmC* phase and further two liquid crystalline phases, antiferroelectric SmC*_{A} and SmI, and a metastable crystal Cr2 reveal. During heating exothermic anomaly in the wide temperature range was observed and ascribed to evolution of Cr2 to the stable crystal Cr1. On further heating both SmC*_{A} and SmC* phases were observed. Thermodynamic parameters were calculated for all phase transitions. During rapid cooling (10 K/min) vitrification of metastable Cr2 crystal at T_{g} = - 115C was registered.
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