Vitrification of the smectic CA* phase and kinetics of cold crystallization investigated for a fluorinated compound with a chiral centre based on (S)-(+)-3-octanol

Abstract

The formation of glass of the anticlinic high-tilted smectic C_A* phase even at low cooling rates (≥2 K min⁻¹) is reported for (S)-4′-(1-ethylhexyloxycarbonyl)biphenyl-4-yl 4-[5-(2,2,3,3,4,4,4-heptafluorobutoxy)pentyl-1-oxy]benzoate. The kinetics of crystallization is investigated via differential scanning calorimetry, polarizing optical microscopy and broadband dielectric spectroscopy. The temperature region of the largest crystallization rate, the activation energy of cold crystallization and the energy barrier of nucleation are determined. The coupling of the characteristic crystallization time with the α-relaxation time is studied. A high fragility index equal to 139 is obtained for this glassformer. Comparison with a very similar glassforming compound, with the chiral centre based on (S)-(+)-2-octanol instead of (S)-(+)-3-octanol, is presented.