We studied the durability against the repetition of image formation and deletion by crosslinking of the polymer in thermoreversible recording media composed of a polymeric film with dispersed long-chain molecules. These media have two different optical states, transparent or light scattering, depending on the thermal history. However, the media have the problem that the densities of the images change and the images become invisible as the number of repetitions of image formation and deletion increases. By observation of the internal structures in the recording layers, it was clarified that the deterioration of the image is caused by the particle growth of long-chain molecules in the recording layer; the particles grow by the heat and shear stress applied from the thermal printhead. Next, the properties of the recording layer crosslinked with electron beam irradiations were investigated, and it was clarified that the crosslinked recording layer did not soften very much at a high temperature. A high degree of crosslinking of the layer was obtained by applying multifunctional monomers, and the durability against the repetition was improved to 1000 times, at which the image contrast hardly changed from that before the repetitive experiment by the crosslinking.