The invention relates to a method for manufacturing a flat polymeric stack, said stack comprising one or more first and one second layer of (co)polymer (20, 30) stacked one on the other, the first underlying (co)polymer layer (20) not having undergone any prior treatment allowing its crosslinking, at least one of the (co)polymer layers initially being in a liquid or viscous state, said method being characterized in that the upper layer (30), known as the top coat (TC), is deposited on the first layer (20) in the form of a prepolymer composition (pre-TC), comprising one or more monomer(s) and/or dimer(s) and/or oligomer(s) and/or polymer(s) in solution, and in that it is then subjected to a heat treatment capable of causing a crosslinking reaction of the molecular chains within said layer (30, TC).