The formulation and solution of fundamental problems of the study of transport phenomena in micro-and nano-porous gels are considered. To study the diffusion in the gels the optical methods are used. This method allows a real-time visualization of the introduced impurities spreading in gels. It is found that the decomposition of the spectrum of the reflected radiation in the optical range allows one to get more information not only about the nature of the diffusion distribution of the considered impurities, but also on the state of the gel itself. Investigated gels are of different lifetimes, whereby a strong influence of these parameters on the rate of diffusion is identified. Relaxation processes must also be taken into account in mass-transfer models describing diffusion in gels. The time-dependent model of diffusion laws is of particular interest. Its application to the modeling of mass transfer processes will bring further understanding of cause and effect relationship of relaxation and diffusion processes.
