Competition between coordination changing network formers in barium borogermanate optical glasses

We propose herein to measure the structure of a series of barium borogermanate glasses, using neutron diffraction and pair distribution function determination, in order to explore the competition between B and Ge for modifier oxygen. In particular, a tie-line is chosen between the B-O and Ge-O coordination number maxima in the borate and germanate glass endmembers respectively, such that all four network modification mechanisms can in principle be active (that is, increases in B-O and Ge-O coordination numbers, as well as formation of non-bridging oxygen on B and Ge).
This proposal will support RB2520089 aimed at temperature dependent structure measurements in the glassy, supercooled liquid and molten states, for a smaller number of compositions. Both proposals will form part of the PhD thesis work of Reuben Tosh, a recently successful applicant to the ISIS Facility Development studentship jointly funded by ISIS and University of Nottingham, with Dr. Oliver Alderman and Dr. Emma Barney as respective supervisors. This is a resubmission of RB2520091 which scored very highly in the previous round, but was not awarded time based on the fair use concept, given that the same PI was awarded time for two other proposals on the same instrument.