Effect of norbornene content on laser ablation of cyclic olefin copolymers

The ablation of cyclic olefin copolymers (COC) by 5 ns/248 nm laser has been examined as a function of norbornene content (61–82 wt.%). The dependence of ablation rate on laser fluence, repetition rate and pulse number has been determined over the range of composition of the copolymers. The ablation rate has increased logarithmically with laser fluence in accordance with the Beer–Lambert relationship. An increase in norbornene content has resulted in an increase in ablation rate and a decrease in threshold fluence. These trends have been attributed to a higher intramolecular rigidity of the chain structure in COC with increasing norbornene content. The morphology of the ablated surfaces was characterised by the formation of voids at high norbornene contents.