Temperature dependent structure of molten borates: application to sealing glass compositions

We propose to measure the structure of barium borate and borosilicate glasses and melts in order to further develop and extend the applicability of our structure-property models in this commercially important class of materials. The proposed compositions are simplified sealing glasses, and will be studied over their expected operating temperature ranges in solid oxide fuel cells, and beyond. The data are expected to yield enthalpy and entropy changes for the sp3-sp2 boron isomerization reaction, for comparison to existing results for lithium and sodium borates. Of interest are the extent to which the presence of barium as modifier cation, and silica as an additional network former affect the temperature dependence of the sp3 boron fraction (N4), which is a crucial structural parameter in governing many important physical properties.