Holbrook C, Chakraborty Shibalik, Ravindren S, Boolchand P, Goldstein Jonathan T, Stutz C E
AFRL/RYDP, 2241 Avionics Circle, B620, Wright-Patterson AFB, Ohio 45433-7707, USA.
Department of Electrical and Computing Systems, College of Engineering and Applied Science, University of Cincinnati, Cincinnati, Ohio 45221-0030, USA.
J Chem Phys. 2014 Apr 14;140(14):144506. doi: 10.1063/1.4869348.
We examine variations in the glass transition temperature (T(g)(x)), molar volume (V(m)(x)), and Raman scattering of titled glasses as a function of modifier (BaO) content in the 25% < x < 48% range. Three distinct regimes of behavior are observed; at low x, 24% < x < 29% range, the modifier largely polymerizes the backbone, T(g)(x) increase, features that we identify with the stressed-rigid elastic phase. At high x, 32% < x < 48% range, the modifier depolymerizes the network by creating non-bridging oxygen (NBO) atoms; in this regime T(g)(x) decreases, and networks are viewed to be in the flexible elastic phase. In the narrow intermediate x regime, 29% < x < 32% range, T(g)(x) shows a broad global maximum almost independent of x, and Raman mode scattering strengths and mode frequencies become relatively x-independent, V(m)(x) show a global minimum, features that we associate with the isostatically rigid elastic phase, also called the intermediate phase. In this phase, medium range structures adapt as revealed by the count of Lagrangian bonding constraints and Raman mode scattering strengths.
我们研究了在25% < x < 48%范围内，标题玻璃的玻璃化转变温度（T(g)(x)）、摩尔体积（V(m)(x)）和拉曼散射随改性剂（BaO）含量的变化。观察到三种不同的行为模式；在低x值，即24% < x < 29%范围内，改性剂主要使主链聚合，T(g)(x)升高，这些特征我们将其与应力刚性弹性相联系。在高x值，即32% < x < 48%范围内，改性剂通过产生非桥氧（NBO）原子使网络解聚；在这个模式下T(g)(x)降低，并且网络被认为处于柔性弹性相。在狭窄的中间x区域，即29% < x < 32%范围内，T(g)(x)呈现出几乎与x无关的宽泛全局最大值，拉曼模式散射强度和模式频率变得相对与x无关，V(m)(x)呈现出全局最小值，这些特征我们将其与等静压刚性弹性相联系，也称为中间相。在这个相中，如通过拉格朗日键合约束计数和拉曼模式散射强度所揭示的，中程结构会发生适应性变化。
