Abstract: The invention concerns a process for the treatment of cross-linked polymeric materials based on E.V.A. (ethylene vinyl acetate) with a view to obtaining polymeric fragments having a lower molecular mass.The process consists of incorporating the polymeric materials, after reduction to a particulate form, in a solvent, notably aromatic and/or halogenated, suitable for diffusing into the interior of the polymeric network and for swelling the latter, and subjecting the reaction medium to a stream of ozone.This process ensures a controlled cleavage of the cross-linked molecules without total destruction of the polymer or disruption of the functional groups. The products obtained may notably be used as modifying agents for hydrocarbon binders or aggregates treated with a hydraulic binder or again as coating binders for granulates.