  One of hallmark features of glass forming ultraviscous liquids is the
decoupling between translational and orientational dynamics. This report
presents studies of this phenomenon in glycerol, a canonical molecular glass
former, heading for the impact of two exogenic factors: high pressures up to
extreme 1.5 GPa and silver (Ag) nanoparticles (NP). The analysis is focused on
the fractional Debye-Stokes-Einstein (FDSE) relation $\sigma(T,P)*(\tau(T,P))^S
= const$, linking DC electric conductivity $(\sigma)$ and primary $(\alpha)$
relaxation time $(\tau_\alpha)$. In glycerol and its nanocolloid (glycerol with
Ag-NP) under atmospheric pressure only the negligible decoupling $(S = 1)$ was
detected. However, in the compressed nanocolloid a well-defined transformation
(at P = 1.2 GPa) from $S \thickapprox 1$ to the very strongly decoupled
dynamics $(S \thickapprox 0.5)$ occurred. For comparison, in pressurized 'pure'
glycerol the stretched shift from $S \thickapprox 1$ to $S \thickapprox 0.7$
took place. This report presents also the general discussion of FDSE behavior
in ultraviscous liquids, including the new link between FDSE exponent,
fragility and the apparent activation enthalpy and volume.

Soft Condensed Matter