The structure and evolution of grain boundaries underlay the nature of polycrystalline materials. Here an experimental apparatus and light reflection technique were described for measuring disorder at grain boundaries in optically clear material in thermodynamic equilibrium. The approach was demonstrated using ice bicrystals. Crystallographic orientation was measured for each ice sample. The type and concentration of impurity in the liquid could be controlled and the temperature could be continuously recorded and controlled over a range near the melting point. The general methodology was appropriate for a wide variety of materials.

A Direct Optical Method for the Study of Grain Boundary Melting. E.S.Thomson, J.S.Wettlaufer, L.A.Wilen: Review of Scientific Instruments, 2009, 80[10], 103903