A composition is also provided that includes mercapto modified resin; aliphatic urethane acrylate; a multifunctional crosslinking agent; photoinitiator; and a hindered amine light stabilizer. The composition provides a fast curing coating that utilizes photopolymerization reactions using a variety of light sources such as low energy consuming and environmentally-friendly UV-LED and sunlight. Features of the coating include clarity, hardness, non-yellowing, scratch resistance, and complete surface cure as well as outstanding adhesion to substrates such as plastic, wood, stone and metal.