  Nearly all glass-forming liquids feature, along with the structural
alpha-relaxation process, a faster secondary process (beta-relaxation), whose
nature belongs to the great mysteries of glass physics. However, for some of
these liquids, no well-pronounced secondary relaxation is observed. A prominent
example is the archetypical glass-forming liquid glycerol. In the present work,
by performing dielectric spectroscopy under superhigh pressures up to 6 GPa, we
show that in glycerol a significant secondary relaxation peak appears in the
dielectric loss at P > 3 GPa. We identify this beta-relaxation to be of
Johari-Goldstein type and discuss its relation to the excess wing. We provide
evidence for a smooth but significant increase of glass-transition temperature
and fragility on increasing pressure.
