Working with capacitors produced with thin organic layers (orthophenanthroline with three stearic chains) significant variations were observed in parallel conductance and capacitance in the neighborhood of the transition pointT=35 °C. An investigation of conductance properties in alternating current revealed that these layers are the site of ion relaxation phenomena between two equilibrium positions separated by a potential barrier. A sudden drop in activation energy was observed at 35 °C, falling from a valueE1=1.25 eV toE2=0.65 eV. This variation, attributed to a phase change, leads to a rapid increase in capacitance and conductanceGin the neighborhood of 35 °C (&Dgr;G/G≳50%/d °C). The phenomenon is reversible, and the structure oscillates between two stable states, depending on temperature.