2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/186025General first- and higher-order intertwining relations between non-stationary one-dimensional Schrödinger operators are introduced. For the first-order case it is shown that the intertwining relations imply some hidden symmetry which in turn results in a $R$-separation of variables. The Fokker-Planck and diffusion equation 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.18 pages, LaTeX209Quantum PhysicsHigh Energy Physics - TheoryMathematical Physicstext