Ashwin Shahani (Cornell undergrad) and Xinwei Wu working on sodium tracer diffusion annealing

1. Sodium Tracer Diffusion Measurements in Sodium Boroaluminosilicate Glasses and the Influence of Water on itSteve W. Martin, Iowa State University, DMR 0710564 • to better understand the Mixed Glass Former Effect (MGFE), tracer diffusion measurements using the radioactive iso-tope Na-22 were performed on two sets of sodium boroaluminosilicateglasses of the type[(Na2O)0.71(B2O3)0.24(Fe2O3)0.05]0.2[(SiO2)x(Al2O3)1−x]0.8 and [(Na2O)0.743(B2O3)0.253(As2O3)0.004]0.18[(SiO2)x(Al2O3)1−x]0.82with x varying from 0.8 to 1 • glass samples: prepared and provided by Corning Inc. • tracer diffusion coefficients of Na-22 in glasses pre-annealed at Tg for 5 hours were measured as a function of composition at temperatures between 198 and 350 °C • activation enthalpies and pre-exponential factors were obtained for different glass compositions • the kinetics of the uptake of water from moist air at elevated temperatureswas found to be diffusion controlled pre-annealing time dependence (left) and composition and temperature dependences (right) of tracer diffusion coefficients determined for the diffusion of sodium in sodium boroaluminosilicateglasses examples for the kinetics of the uptake of water by glasses of interest in this study at300 °C in moist air

2. Sodium Tracer Diffusion Measurements in Sodium Boroaluminosilicate Glasses and the Influence of Water on it Steve W. Martin, Iowa State University, DMR 0710564 • two undergraduate students from Cornell University participate in this program in addition to Xinwei Wu as a graduate student • a collaboration with scientists from Corning Inc. exists; Corning Inc. prepared glass samples and provided results of NMR measurements for structural information on glasses • an international collaboration within the framework of the Materials World Network (MWN) Mixed Glass Former Effect with scientists from three European universities at Chalmers (Sweden), and at Münster and Ilmenau (Germany) is in place • in addition there is a collaboration with two groups in the U.S. (Steve Martin, Iowa State University and ValeriPetkov, Central Michigan University) AshwinShahaniandYee Ting Tse (Cornell undergrads) working with the FTIR instrument available for measurements on the concentration of water in glasses AshwinShahani(Cornell undergrad) and Xinwei Wu working on sodium tracer diffusion annealing