Grant: Discovery Grants Program - Individual

Liquid and glassy oxide mixtures are used ubiquitously in applications ranging from the mundane to advanced photonics. One example is boron oxide and water. This mixture is part of the flux needed to solder copper pipes, and it is commonly used as an effective flame retardant: while dry at room temperature, it releases water upon heating. During these applications the material is in its hot liquid state, and our objective is to measure the properties these hot liquids. Almost no experimental work has been done on hot B2O3:H2O mixtures, perhaps due to the need to contain several atmospheres of pressure from the released steam while carrying out the measurements. Pure B2O3 glass is an ""inorganic polymer""; a whole batch of material is actually one single molecule, consisting of a continuous random network of covalent bonds. If one looks at a ""snapshot"" of water at one moment, it is also a continuous random network of bonds, but in water the links are much weaker hydrogen bonds interlinking H2O molecules. By continuously adjusting the ratio of B2O3 to H2O we switch gradually from one type of network to the other. One of our objectives is to find the minimum amount of B2O3 required for forming a continuous network of covalent bonds across the whole sample. We will also investigate the basic properties of two binary oxide mixtures that are important for high temperature and photonics applications: SiO2:GeO2 and SiO2:Al2O3. Varying the composition of these materials is necessary to tune the optical properties. We will make use of our unique experimental ability to monitor the melting of glasses (the glass transition) at extremely high temperatures with synchrotron radiation. The energy efficiency of engines increases with temperature. We will contribute towards developing novel high-temperature materials by searching for the glass with the highest melting point, starting with mixtures of SiO2 and Al2O3.