Vivid Manifestation of Nonergodicity in Glassy Propylene Carbonate at High Pressures

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• 作者：Igor V. Danilov ; Elena L. Gromnitskaya ; Vadim V. Brazhkin
• 刊名：Journal of Physical Chemistry B
• 出版年：2016
• 出版时间：August 4, 2016
• 年：2016
• 卷：120
• 期：30
• 页码：7593-7597
• 全文大小：322K
• 年卷期：0
• ISSN：1520-5207

文摘

As glasses are nonergodic systems, their properties should depend not only on external macroparameters, such as P and T, but also on the time of observation and thermobaric history. In this work, comparative ultrasonic studies of two groups of molecular propylene carbonate glasses obtained by quenching from a liquid at pressures of 0.1 and 1 GPa have been performed. Although the difference in the densities of the different groups of glasses is small (3–5%), they have significantly different elastic properties: the difference in the respective bulk moduli is 10–20%, and the difference in the respective shear moduli is 35–40% (!). This is due to the “closure of nanopores” in the glass obtained at 1 GPa. The pressure and temperature derivatives of the elastic moduli for these groups of glasses are also noticeably different. The glass-transition temperatures of glasses from different groups differ by 3–4 K. The character of absorption of ultrasound waves near the glass-transition temperature also differs for different groups of glasses. The differences in the behaviors of these groups of glasses disappear gradually above the glass-transition temperature, in the region of a liquid phase. Glasses with a wide diversity of physical properties can be obtained using various paths on the (T,P) diagram.