Intertwining relations of non-stationary Schrodinger operators

General first- and higher-order intertwining relations between non-stationa ry one-dimensional Schrodinger operators are introduced. For the first-orde r case it is shown that the intertwining relations imply some hidden symmet ry which in turn results in an R-separation of variables. The Fokker-Planck and diffusion equations are briefly considered. Second-order intertwining operators are also discussed within a general approach. However, due to its complicated structure only particular solutions are given in some detail.