Variations of the effective activation energy (E_α) throughout the glass transition were determined for 1,2-propanediamine (12PDA), 1,2-propanediol (12PDO) and its solutions of LiBF₄ by applying an isoconversional method to differential scanning calorimetry (DSC) data. For 12PDA, E_α is found to markedly decrease from 660 to 188 kJ mol^—1 throughout the glass transition, whereas 12PDO does not show such drastic change in E_α, which remains at around 145 kJ mol^—1. Although the two simple liquids are similar in molecular structure and size, the cooperative dynamics in the glass transition can be quite different because of differences in the strength or stability of hydrogen-bonding structure between them. We also have discovered that the addition of LiBF₄ significantly affects E_α for 12PDO. The glass transition dynamics are affected more by adding LiBF₄ at an early stage of the glass-to-liquid transition rather than at later stages. As the mole fraction x of LiBF₄ increases, the value of E_α initially increases, but it decreases dramatically during the glass transition. The expansion of cooperativity and its fragmentation, which are reflected in the abrupt change in E_α, can be explained in terms of competition between the hydrogen-bond networks of the alcohol solvent and the ionic interactions due to the added salt. The variability of E_α with temperature is found to correlate strongly with the kinetic fragility.

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Fast scanning chip calorimetry (FSC) experiments are reviewed in terms of the melting of semi-crystalline polymers examined over a wide range of heating rates. The analysis method of melting kinetics is summarized and it is shown that the heating rate dependence of melting temperatures revealed that there are two crystal populations with distinct melting kinetics for isothermally crystallized PA6 and PEEK. Some semi-crystalline polymers showed the following relation between the melting peak temperature, T_m, and the crystallization temperature, T_iso; T_m = T_iso + δT with a constant δT. Quantitative consideration of this issue is discussed on the basis of the Lauritzen-Hoffman standard model of polymer crystallization. We also discuss a method for obtaining the lamellar thickness distribution (LTD) of linear PE by using FSC.

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Recently terahertz spectroscopy becomes popular not only in optical science but also in material science and engineering. Several spectrometers are now commercially available, and anybody has a chance to use this new technique. This review provides four examples of our recent works investigating physical properties of molecular solids using terahertz spectroscopy. The topics are “kinetics of polymorphic transition of cyclohexanol”, “molecular motion of nylon-6 in the crystalline domain”, “structural change in giant cluster of multinuclear metal complex”, and “dynamics of Li⁺ ion encapsulated in C₆₀ fullerene”. The molecular motions observed uncover the structural change, the coupling of motions, and the dynamics of loosely bound atoms or molecules. Temperature dependences of the terahertz spectra reveal the changes in these factors, and it is suggested that terahertz spectroscopy goes well with calorimetry.

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Tea beverages such as green, oolong and black teas are very popular in the world. Recently, green tea extract-based dietary supplements including a large amount of green tea polyphenol (GTP) have been widely consumed to expect beneficial health as anti-aging, weight reduction and etc. Although tea beverages are considered to be innocuous, the large ingestion of GTP from dietary supplements and the administration of a drug with GTP often produce some serious effects. The GTP with high physiological activity can interact with some drugs to affect the absorption, bioavailability and efficacy of the drug. Therefore, it is very important on medicinal treatment to analyze the compatibility and the mechanism for drug interaction with GTP using isothermal titration microcalorimetry (ITC) and molecular modeling calculation (MMC). It is concluded that ITC is the most suitable and powerful measurement method to analyze interaction between drugs and bioactive substances in tea beverage, supplement and health food. ITC can bring some useful information in medical treatment and elucidate the drug interaction at the molecular level by combination with MMC.

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Recent progress on the dielectric studies of pure ice and partially crystallized aqueous mixtures are reviewed. Dielectric relaxation of ice has been controlled by preparation methods. This implies that the dynamics of ice seems to be affected by the impurity content in ice crystal. In dilute gelatin-water mixtures with gelatin concentration up to 5 wt%, dielectric relaxation processes of ice have been found, and those behavior depend strongly on gelatin concentration. In partially crystallized aqueous protein mixtures, three dielectric relaxation processes have been found and these are originated from dynamics of uncrystallized water, ice, and hydrated solute molecules.

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