Process for radiation cured conjugated diene-vinyl aromatic hydrocarbon block copolymers

In a process of curing epoxidized polymers of conjugated dienes which contain aromatic moieties by exposing the polymers to ultraviolet radiation in the presence of a photoinitiator, the improvement which comprises reducing the amount of irradiation necessary to achieve an effective cure by adding a small but effective amount of a photosensitizer which absorbs UV radiation in a wavelength range which is not obscured by the polymer to the polymer prior to or during irradiation.