Wataru Takeda

Wataru Takeda is a senior student at Coe College in Cedar Rapids, Iowa. He transferred to Coe College after two years in The Open University of Japan. He is interested in structural models of vitreous networks and has been working on analysing the lithium borate glass system by using constraint theory this summer. He likes to play soccer for fun, and he fully enjoyed watching the World Cup this summer.


Lithium Borate Glass Analysis by the Topological Constraint Model
Wataru Takeda and Steve Feller
Physics Department, Coe College, Cedar Rapids, Iowa 52402, USA

The topological constraint model has been applied to alkali borate1 and alkali–alkaline earth–borosilicate glass systems2. However, this model has not been applied to the calculation of the glass transition temperature (Tg) and the average coordination of the network forming cation for a wide range of compositions due to the difficulty of understanding the structural evolution of vitreous system of borate glasses. This study predicts Tg and the average coordination of the network forming cation, boron, by using the Jellison and Bray3, the Yun and Bray4, the Krogh–Moe5 and S. A. Feller model of structure6 over a wide range of compositions (0≤R≤1.86, where R is the molar ratio of modifier to boron oxide).


  1. John C. Mauro, Prabhat K. Gupta and Roger J. Loucks, Composition dependence of glass transition temperature and fragility. II. A topological model of alkali borate liquids, J. Chem. Phys. 130, 234503 (2009).
  2. M. Smedskjaer, John C. Mauro, R. E. Youngman, C. L. Hogue, M. Potuzak and Y. Yue, Topological principles of borosilicate glass chemistry, J. Phys. Chem. B 115, 12930 (2011).
  3. E. Jellison, Jr., and P. J. Bray, A structural interpretation of B10and B11 NMR spectra in sodium borate glasses, J. Non-Crystalline Solids 29, 187 (1978)
  4. H. Yun and P. J. Bray, Nuclear magnetic resonance studies of the glasses in the system Na2O B2O3 SiO2, J. Non-Crystalline Solids 27 (1978)
  5. Krogh–Moe, Interpretation of the infrared spectra of boron oxide and alkali borate glasses, Phys. Chem. Glasses 6 46 (1965).
  6. J. Bray, S. A. Feller, G. E. Jellison, Jr., Y. H. Yun. B10 NMR studies of the structure of the glasses J. Non-Crystalline Solids 38 & 39 (1980).