The atomic arrangement of glass-forming liquids changes as stable liquids are supercooled to the point of vitrification. These changes in metastable liquid structure influence important physical properties such as viscosity. Diffraction methods can be used to provide amorphous and glass structures and these methods can be extended to the liquid state. Containerless techniques can be combined with diffraction methods to considerable advantages since the contribution of sample containers can be completely eliminated from the overall scattered signal. High energy X-ray diffraction (HEXRD) uses high incident energies and provides bulk diffraction data to high values of scattering vector. The data acquisition times are short and “dynamic” measurements of stable and supercooled liquids can be made by combining HEXRD with containerless processing.

Combined HEXRD and containerless techniques have been applied successfully to a number of refractory oxide systems as a function of composition and temperature, these include Al₂O₃-SiO_2, SiO₂-CaO and SiO₂-MgO and the polymorphic system Al₂O₃-Y₂O₃. Control of pO2 adds a further dimension to phase space and has allowed studies of liquids containing iron and other transition metals to be made. The scope of these studies has recently been extended to include tellurite systems to evaluate changes in the underlying tellurite network and the clustering of Te-O polyhedra, these are correlated with viscosity increase and a transition form an ergodic to non-ergodic liquid regime.

Studies of molten salts combine diffraction with state-of-the-art Molecular Dynamics simulations and allow full descriptions of the liquid structure and dynamics. These studies show the critical role of transient, low-dimensional structures in controlling liquid viscosity.