A time resolved high energy X-ray diffraction study of cooling liquid SiO₂

The evolution of the X-ray structure factor and corresponding pair distribution function of SiO₂ has been measured upon cooling from the melt using high energy X-ray diffraction combined with aerodynamic levitation. Small changes in the position of the average Si-O bond distance and peak width are found to occur at ∼1500(100) K in the region of the calorimetric glass transition temperature, T_g and the observed density minima. At higher temperatures deviations from linear behavior are seen in the first sharp diffraction peak width, height and area at around 1750(50) K, which coincides with the reported density maximum around 1.2T_g.