Thermodynamic Study on Simple Molecular Glasses

• Yamamuro Osamu

  Institute for Solid State Physics, University of Tokyo

• Tatsumi Soichi

  Institute for Solid State Physics, University of Tokyo Present address: Graduate School of Science, Tokyo Institute of Technology

Bibliographic Information

Other Title

• 単純分子ガラスの熱力学的研究
• タンジュン ブンシ ガラス ノ ネツ リキガクテキ ケンキュウ

Abstract

We have combined our recent calorimetric works on vapor-deposited simple molecular glasses and our previous works on ordinary molecular glasses to investigate the universal thermodynamic feature of molecular glasses. Following a brief review for the studies on glass transitions, we describe how the vapor-deposition method is useful for simple molecular glasses. Then, we mention the structure of the adiabatic calorimeter recently developed for vapor-deposited samples. The heat capacities C_p of vapor-deposited carbon tetrachloride (CCl₄), propene (CH₂=CHCH₃) and propane (CH₃CH₂CH₃) are shown. Low-energy excitations characteristic to glasses were observed in all glassy samples. Glass transitions appeared in propene and propane at 56 K and 45 K, respectively; 45 K is the lowest record of Tgs of molecular glasses. The configurational heat capacity ΔC_p and entropy S_c are calculated from the C_p data of ten molecular glasses. The universal feature for the temperature dependence of ΔC_p is demonstrated by scaling temperature using the Kauzmann temperature T_K. The size z* of cooperatively rearranging region (CRR) is also calculated based on the Adam-Gibbs theory. They are increasing with decreasing temperature and frozen at each T_g. The frozen numbers z*(0) are 3-7 molecules and depend on (T_g-T_K)/T_K; the larger (T_g-T_K)/T_K is, the smaller z*(0) becomes. Thus, the present work has demonstrated the universal thermodynamic feature of molecular glasses and indicated the validity of the Adam-Gibbs theory based on the experimental data.

Journal

• Nihon Reoroji Gakkaishi

  Nihon Reoroji Gakkaishi 40 (3), 137-142, 2012

  The Society of Rheology, Japan

Keywords

• Molecular glass
• Glass transition
• Vapor deposition
• Heat capacity
• Configurational entropy

Details

• CRID: 1390001205096404992
• NII Article ID: 130001880134
• NII Book ID: AN00198812
• DOI: 10.1678/rheology.40.137
• COI: 1:CAS:528:DC%2BC38Xht1Ors77F
• ISSN: 21864586
• ISSN: 03871533
• NDL BIB ID: 023846431
• Web Site: http://id.ndl.go.jp/bib/023846431
• Web Site: https://ndlsearch.ndl.go.jp/books/R000000004-I023846431
• Web Site: https://www.jstage.jst.go.jp/article/rheology/40/3/40_137/_pdf
• Text Lang: ja
• Data Source:
  • JaLC
  • NDL
  • Crossref
  • CiNii Articles
  • KAKEN
• Abstract License Flag: Disallowed