The present invention is drawn to a process of drilling organic glasses. The process comprises (a) providing an organic glass substrate; (b) providing onto at least one surface of said organic glass substrate optionally via an adhesive layer selected from the group consisting of pressure sensitive adhesives and hot melt adhesives, a polymer film having an elastic modulus of equal to or less than 3 GPa in at least one direction and a E*h2 equal to or more than 3.5 N in at least one direction, E and h being respectively the elastic modulus and the thickness of the thermoplastic polymer film; and (c) drilling a hole through the organic glass substrate and polymer film by means of a drill.