Generalized single-parameter aging tests and their application to glycerol

Physical aging of glycerol following temperature jumps is studied by dielectric spectroscopy at temperatures just below the glass transition temperature. The data are analyzed using two single-parameter aging tests developed by Hecksher et al. [J. Chem. Phys. 142, 241103 (2015)]. We generalize these tests to include jumps ending at different temperatures. Moreover, four times larger jumps than previously are studied. The single-parameter aging tests are here for the first time applied to a hydrogen-bonded liquid. We conclude that glycerol obeys single-parameter aging to a good approximation.