Surface Dynamics of Liquids in Nanopores

${}^2$H NMR relaxation of a selectively deuterated polar molecule confined to a set of calibrated nanoporous silica glasses is reported. These experiments, combined with the consideration of different time scales in the theory of surface relaxation, show how confinement effects can provide detailed information on the rotational dynamics of temporarily adsorbed liquid layers in presence of biphasic fast exchange. In particular, the results show the existence of an orientational order parameter within the wetting monolayer.