  Glycerol and trehalose-glycerol binary solutions are glass-forming liquids
with remarkable bioprotectant properties. Incoherent quasielastic neutron
scattering (QENS) is used to reveal the different effects of nanoconfinement
and addition of trehalose on the molecular dynamics in the normal liquid and
supercooled liquid phases, on a nanosecond timescale. Confinement has been
realized in straight channels of diameter D=8 nm formed by porous silicon. It
leads to a faster and more inhomogeneous relaxation dynamics deep in the liquid
phase. This confinement effect remains at lower temperature where it affects
the glassy dynamics. The glass transitions of the confined systems are shifted
to low temperature with respect to the bulk ones. Adding trehalose tends to
slow down the overall glassy dynamics and increases the non-exponential
character of the structural relaxation. Unprecedented results are obtained for
the binary bioprotectant solution, which exhibits an extremely non-Debye
relaxation dynamics as a result of the combination of the effects of
confinement and mixing of two constituents.
