Abstract: A multi color, photoactive, color changing plastic, coating or ink, composition comprising both a photochromic material and a photosensitive chromogenic system is provided which will undergo a sequence of color changes upon exposure to ultraviolet radiation. Also provided is an ultraviolet indicator or dosimeter comprising the color changing composition.

Abstract: A multi color, photoactive, color changing plastic, coating or ink, composition comprising both a photochromic material and a photosensitive chromogenic system is provided which will undergo a sequence of color changes upon exposure to ultraviolet radiation. Also provided is an ultraviolet indicator or dosimeter comprising the color changing composition.

Abstract: A method is provided for enhancing the gas barrier properties of substrates such as materials used in packaging, by applying a composition comprising a vinyl alcohol/vinyl amide copolymer, a cross linker and, optionally, a diacrylate or other polyacrylate and a photo initiator to the material and curing the composition by irradiation with UV light, visible light, IR irradiation and/or electron beam or by exposure to heat. The method includes the optional step of subjecting the material to a low-temperature plasma discharge or a corona discharge prior to applying the composition. The method provides, for example, packaging materials, such as, flexible packaging materials such as plastic films producing packaging materials with excellent gas barrier properties, for example oxygen barrier properties, which are readily printed upon.