A model for the fragility of the melts |
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Authors: | Aniya M |
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Institution: | (1) Department of Physics, Faculty of Science, Kumamoto University, Kumamoto 860-8555, Japan |
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Abstract: | The concept of fragility has been used widely to characterize the temperature dependence of the viscosity of glass forming
materials. However, the physical background that determines the degree of fragility is still not well understood. In the present
study an expression for the fragility is derived based on a simple model of the melt. According to the model, the fragility
is determined by the relaxation of structural units that form the melt, and is described in terms of the bond strength (E
0), coordination number (Z
0), and their fluctuations (ΔE and ΔZ). It is shown that a strong system is characterized by large value of total bond strength (Z
0
E
0) and small value of its fluctuation ((ΔZ)2(ΔE)2). On the other hand, a fragile system is characterized by small value of total bond strength and large value of its fluctuation.
This revised version was published online in August 2006 with corrections to the Cover Date. |
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Keywords: | fragility viscosity glass forming materials |
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