Ionizing radiations, chain scission degradation mechanism

It should be pointed out that Norrish-type 1 degradation is not efficient in PMMA, hence its rather low sensitivity to ionizing radiation, DUV radiation, and electron-beam radiation. For instance, it requires a dose of 3400 mJ/cm at 240 nm to get it fully exposed and developable. Experiments by Guillet and co-workers " have revealed that the cause of the inefficiency is the a-fission step in the chain scission mechanism. 

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