  Ultrafast synchrotron microtomography has been used to study in-situ and in
real time the initial stages of silicate glass melt formation from crystalline
granular raw materials. Significant and unexpected rearrangements of grains
occur below the nominal eutectic temperature, and several drastically different
solid-state reactions are observed to take place at different types of
intergranular contacts. These reactions have a profound influence on the
formation and the composition of the liquids produced, and control the
formation of defects.
