Discovery of crystal nucleation proceeding much below the glass transition temperature in a supercooled liquid

A crystal nucleation process of liquid 3,3'-dimethoxy-4,4'-bis(2,2-diphenylvinyl) biphenyl was found by DSC to proceed in the range 170-280 K. The lowest temperature at which the nucleation occurs is lower by 175 K than the glass transition temperature (T-g = 345 K); this rejects a common assumption that the nucleation rate Is dominated by the viscosity, namely the alpha-molecular rearrangement process, of liquid. The beta-process, rather than the alpha-process, is discussed as a candidate for dominating the rate of the crystal nucleation and probably the rate of crystal growth as well. Copyright (C) 1996 Elsevier Science Ltd.