The liquid-glass transition in a strong glassformer
- Chalmers Univ. of Technology, Goeteborg (Sweden)
- Royal Institute of Technology, Stockholm (Sweden)
- Max-Planck-Institut fuer Polymerforschung, Mainz (Germany)
Based on light and neutron scattering observations the authors describe the relaxation dynamics of a strong glassformer, B{sub 2}O{sub 3}. The experimental information is compared with predictions of the mode coupling theory (MCT) of the liquid-glass transition in order to test whether its success in describing fragile systems can be extended also to strong glassformers. The data show the predicted two-step relaxation, and the time decay follows qualitatively the MCT functional form. Also, there is convincing evidence of some cross-over temperature in the dynamics that may be identified as the critical temperature T{sub c} of MCT. There are however some distinct differences. T{sub c} is not as sharply defined in B{sub 2}O{sub 3} and it is at a considerably higher temperature (T{sub c} = 1.6T{sub g}) than in fragile ones (T{sub c}{approx}1.2 T{sub g}). The authors suggest this to be characteristic for strong glassformers in general due to their broader glass transformation range. Moreover, a strong vibrational contribution, the boson peak, affects the high frequency dynamics which results in significant deviations from the MCT master curve. In strong systems the boson peak is generally more pronounced. Therefore, a successful description of the liquid-glass transition in strong systems has to address the influence of vibrational modes on the relaxation dynamics. 60 refs., 10 figs.
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 391362
- Journal Information:
- Transport Theory and Statistical Physics, Journal Name: Transport Theory and Statistical Physics Journal Issue: 6-8 Vol. 24; ISSN TTSPB4; ISSN 0041-1450
- Country of Publication:
- United States
- Language:
- English
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