  A high-resolution calorimetric spectroscopy study has been performed on pure
glycerol and colloidal dispersions of an aerosil in glycerol covering a wide
range of temperatures from 300 K to 380 K, deep in the liquid phase of
glycerol. The colloidal glycerol+aerosil samples with 0.05, 0.10, and 0.20 mass
fraction of aerosil reveal glassy, activated dynamics at temperatures well
above the $T_g$ of the pure glycerol. The onset of glass-like behavior appears
to be due to the structural frustration imposed by the silica gel on the
glycerol liquid. The aerosil gel increases the net viscosity of the mixture,
placing the sample effectively at a lower temperature thus inducing a glassy
state. Given the onset of this behavior at relatively low aerosil density
(large mean-void length compared to the size of a glycerol molecule), this
induced glassy behavior is likely due to a collective mode of glycerol
molecules. The study of frustrated glass-forming systems may be a unique avenue
for illuminating the physics of glasses.
