In this contribution we describe schematically the role of geometrical restrictions in modifying some dynamical properties of probe molecules. We also discuss the basic ideas behind the applications of optical probes in order to sense local morphologies. The restricted geometries we refer to are mainly porous silica gels, but the general methodology and conclusions are applicable to other spatial confinements as well. We focus on two realizations and their theoretical modeling: (a) direct energy transfer between donor and acceptors adsorbed on pore interfaces and (b) quenching of a donor by diffusing acceptors within pore networks. In each case the time evolution of the relaxation process is related to the geometrical restrictions imposed on the participating molecules by the porous structures.