Broadband dielectric response of glycerol and propylene carbonate: a   comparison
  Dielectric data on glycerol and propylene carbonate covering 18 decades of frequency are presented and compared to each other. Both materials exhibit qualitatively similar behavior except for marked differences in the high-frequency region just below the boson peak. The results on both materials are consistent with the mode coupling theory of the glass transition. 
P. Lunkenheimer, U. Schneider, R. Brand, and A. Loidl