Mauro John C, Gupta Prabhat K, Loucks Roger J
Science and Technology Division, Corning Incorporated, Corning, New York 14831, USA.
J Chem Phys. 2009 Jun 21;130(23):234503. doi: 10.1063/1.3152432.
Glass transition temperature and fragility are two important properties derived from the temperature dependence of the shear viscosity of glass-forming melts. While direct calculation of these properties from atomistic simulations is currently infeasible, we have developed a new topological modeling approach that enables accurate prediction of the scaling of both glass transition temperature and fragility with composition. A key feature of our approach is the incorporation of temperature-dependent constraints that become rigid as a liquid is cooled. Using this approach, we derive analytical expressions for the composition (x) dependence of glass transition temperature, T(g)(x), and fragility, m(x), in binary alkali borate systems. Results for sodium borate and lithium borate systems are in agreement with published values of T(g)(x) and m(x). Our modeling approach reveals a natural explanation for the presence of the constant T(g) regime observed in alkali borate systems.
玻璃化转变温度和脆性是由玻璃形成熔体的剪切粘度对温度的依赖性得出的两个重要性质。虽然目前从原子模拟直接计算这些性质是不可行的，但我们已经开发了一种新的拓扑建模方法，该方法能够准确预测玻璃化转变温度和脆性随成分的变化规律。我们方法的一个关键特征是纳入了随温度变化的约束条件，这些约束条件在液体冷却时会变得刚性。使用这种方法，我们推导了二元碱金属硼酸盐体系中玻璃化转变温度T(g)(x)和脆性m(x)随成分(x)变化的解析表达式。硼酸钠和硼酸锂体系的结果与已发表的T(g)(x)和m(x)值一致。我们的建模方法为在碱金属硼酸盐体系中观察到的恒定T(g)区域的存在提供了一个自然的解释。
