Group of Nanomaterials and Microsystems, Physics Department, Universitat Autònoma de Barcelona, 08193 Bellaterra, Spain.
Phys Rev Lett. 2019 Oct 11;123(15):155501. doi: 10.1103/PhysRevLett.123.155501.
Thin film stable glasses transform into a liquid by a moving front that propagates from surfaces or interfaces with higher mobility. We use calorimetric data of vapor-deposited glasses of different thicknesses and stabilities to identify the role of glassy and liquid dynamics on the transformation process. By invoking the existence of an ultrathin intermediate layer whose transformation strongly depends on the properties of both the liquid and the glass, we show that the recovery to equilibrium is driven by the mismatch in the dynamics between glass and liquid. The lifetime of this intermediate layer associated with the moving front is the geometric mean between the bulk transformation time and the alpha relaxation time. Within this view, we explain the observed dependencies of the growth front velocity and the crossover length with both stability and temperature. Extrapolation of these results points towards ordinary thin film glasses transforming via a frontlike transformation mechanism if heated sufficiently fast, establishing a close connection between vapor-deposited and liquid-cooled glasses.
薄膜稳定玻璃通过从具有更高迁移率的表面或界面传播的移动前沿转变为液体。我们使用不同厚度和稳定性的蒸镀玻璃的量热数据来确定玻璃态和液态动力学在转变过程中的作用。通过引入超薄膜中间层的存在，其转变强烈依赖于液体和玻璃的性质，我们表明，恢复到平衡是由玻璃和液体之间的动力学失配驱动的。与移动前沿相关的这个中间层的寿命是体转变时间和α松弛时间的几何平均值。在这种观点下，我们解释了观察到的生长前沿速度和交叉长度与稳定性和温度的依赖性。这些结果的外推表明，如果加热足够快，普通的薄膜玻璃将通过前沿转变机制转变，从而在蒸镀玻璃和液冷玻璃之间建立紧密的联系。
