Viscoelastic Behavior of Inorganic Glass-Formers

无机玻璃形成剂的粘弹性行为

• 批准号: 9530372
• 负责人: Donald Plazek
• 金额: $ 28.62万
• 依托单位: University of Pittsburgh
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1996
• 资助国家: 美国
• 起止时间: 1996-08-15 至 2000-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9530372&HistoricalAwards=false
• 关键词: Viscoelastic; Behavior; Inorganic; Glass; Formers

9530372 Plazek Inorganic network compounds form an important class of glass-formers whose viscoelastic behavior has not been well-studied compared to that of organic polymers and small molecule liquids. The viscoelastic behavior of selected inorganic glass-formers, including selenium, sulfur, boron trioxide, arsenic selenide, arsenic telluride, arsenic sulfide, germanium dioxide, and various compositions of germanium-arsenic- selenium will be examined both above and below their glass transition temperatures (Tg). The establishment of a characteristic variable for glass formation, based on the growing evidence of a common molecular mobility at the glass transition temperature will be attempted. This attempt will entail proper determination of the glass temperatures of these materials during cooling using volume dilatometry and differential scanning calorimetry in order to use the glass transition temperature(Tg)as a corresponding state parameter. The viscoelastic measurements made above Tg are also anticipated to resolve the issue of whether molecular networks are present in some inorganic glasses, and will allow determination of whether molecular moieties in these glasses are fixed or in dynamic equilibrium. The data obtained will also be used to test the generality of the relationship which has been found between the time and temperature dependencies of the viscoelastic behavior of organic materials. Finally the viscoelastic data obtained below Tg, coupled with dilatometry and calorimetric data, will be used to determine whether decoupling of different irreversible processes occurs in inorganic glasses. %%% This research will enhance the understanding of inorganic glass structure and the correlation of structure with properties in an attempt to learn how to control structures to obtain desired properties. Establishing the behavior of these inorganic materials when compared to other glass formers in terms of dynamic states above and below glass transition temperatures is an important goal, and given the fact that the solid-state inorganic materials are similar to silica, the potential impact on innovative technologies such as optical fibers is high. ***

无机网络化合物形成一类重要的玻璃形成剂，与有机聚合物和小分子液体相比，其粘弹性行为尚未得到充分研究。 所选无机玻璃形成剂，包括硒、硫、三氧化二硼、硒化砷、碲化砷、硫化砷、二氧化锗和锗-砷-硒的各种组合物的粘弹性行为将在高于和低于其玻璃化转变温度（Tg）时进行检查。将尝试建立一个玻璃形成的特征变量的基础上，在玻璃化转变温度下的一个共同的分子流动性越来越多的证据。这种尝试将需要适当的确定这些材料的玻璃化温度在冷却过程中使用体积法和差示扫描量热法，以使用玻璃化转变温度（Tg）作为相应的状态参数。还预期在Tg以上进行的粘弹性测量解决了分子网络是否存在于一些无机玻璃中的问题，并且将允许确定这些玻璃中的分子部分是固定的还是处于动态平衡。所获得的数据也将用于测试有机材料的粘弹性行为的时间和温度依赖性之间的关系的一般性。最后，低于Tg得到的粘弹性数据，再加上量热法和量热数据，将被用来确定是否去耦不同的不可逆过程中发生的无机玻璃。 本研究将加深对无机玻璃结构的理解以及结构与性能的相关性，试图了解如何控制结构以获得所需的性能。 确定这些无机材料在高于和低于玻璃化转变温度的动态状态方面与其他玻璃形成剂相比时的行为是一个重要目标，并且鉴于固态无机材料与二氧化硅类似的事实，对创新技术（如光纤）的潜在影响很大。 ***