We carried out an experimental ultrasonic study of polyhydric alcohols with the general chemical formula C_nH_n+2(OH)_n with an increasing number of OH groups: glycerol (n=3), erythritol (n=4), xylitol (n=5), sorbitol (n=6). The baric and temperature dependences of the elastic characteristics of these substances in the crystalline and glassy states were studied both under isothermal compression up to 1 GPa and during the isobaric heating of 77-295 K. For glycerol, glasses were obtained at different cooling rates, glass-liquid transitions were studied at different pressures. All the studied glasses have lower elastic moduli than the same substances in the crystalline state at the same pressure-temperature conditions. We obtained a cascade of glass-supercooled liquid-crystal transitions during heating of glassy erythritol. In the series of substances with n=3,4,5 the bulk moduli show a tendency to decrease with increasing n. However, sorbitol (n=6) unexpectedly has the highest elastic moduli among the studied substances in both the glassy and crystalline states. The studied glassformers show a general tendency to increase the glass transition temperature T_g and the fragility coefficient m with increasing n.

中文翻译：

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高压下的多元醇：弹性特性的比较超声研究


我们对多元醇进行了实验超声研究，其一般化学式为 C_nH_n+2（OH）_n，OH 基团数量不断增加：甘油 （n=3）、赤藓糖醇 （n=4）、木糖醇 （n=5）、山梨醇 （n=6）。研究了这些物质在结晶和玻璃态下弹性特性的气压和温度依赖性，无论是在高达 1 GPa 的等温压缩下还是在 77-295 K 的等压加热过程中。对于甘油，在不同的冷却速率下获得玻璃，在不同的压力下研究玻璃-液体转变。在相同的压力-温度条件下，所有研究的玻璃的弹性模量都比相同物质的结晶状态要低。我们在玻璃状赤藓糖醇的加热过程中获得了玻璃过冷液晶转变的级联反应。在 n=3,4,5 的一系列物质中，体积模量表现出随着 n 的增加而降低的趋势。然而，山梨醇 （n=6） 出乎意料地在研究的玻璃态和结晶态物质中具有最高的弹性模量。所研究的玻璃成型剂显示出随着 n 的增加而增加玻璃化转变温度 T_g 和脆性系数 m 的一般趋势。