Abstract
General aspects of the glass transitions, the dispersions pertaining to the Brownian motions near the glass transition temperature, and the local mode of motions in the glasses of o-terphenyl, triphenylchloromethane, poly (vinyl chloride), and D-sorbitol are discussed. The configurational internal energy and/or the configurational entropy govern the molecular mobility in the supercooled liquids of molecular liquids, including polymer liquids. The intermolecular inefficient spaces of futile interstices among molecules, but not the intramolecular conformational degrees of freedom in polymers, may be the essential origin of the failure of free volume theories for mobility in molecular liquids. The distribution of configurational energy, but not individual small groups and intramolecular chain flexibility, governs the local mode of motions in the molecular glasses, the polymer glasses, and the hydrogen-bonded glasses. A macroscopic way to analyze the contribution from hydrogen bonds is proposed. This explains well the peculiar properties of the molecular mobility and the glass transition in associated liquids.
