Viscoelastic Behavior of Inorganic Glass-Formers

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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. ***