Abstract: This invention relates to a liquid coating composition that is thermally-curable in the presence of oxygen, comprising: a monomer or oligomer containing two or more acrylate and/or methacrylate functional groups; an azo initiator; and oxygen. This invention also relates to a process for coating a substrate comprising the steps of applying a thin film of the foregoing coating composition to said substrate; and heating said coating composition at an effective temperature for an effective period of time to cure said coating composition, said applying and heating steps being conducted in the presence of oxygen.