Temperature-dependent structural arrest of silica colloids in a water–lutidine binary mixture

We study the onset of structural arrest and glass formation in a suspension of silica nanoparticles in a water–lutidine binary mixture near its consolute point. By exploiting the near-critical fluid degrees of freedom to control the strength of an attraction between particles and multispeckle X-ray photon correlation spectroscopy to characterize the particles' collective dynamics, we show that this model liquid undergoes a glass transition both on cooling and on heating, and that the intermediate liquid realizes unusual logarithmic relaxations. We are able to characterize in unprecedented detail how vitrification occurs for the two different glass transitions observed, and draw comparisons to recent theoretical predictions for glass formation in systems with attractive interactions.