Photochromic article and method of preparation

The present invention relates to photochromic articles including optical articles such as sunglasses, spectacles and piano lenses, windows, vehicle and aircraft transparencies, plastic film and coating. The present invention relates in particular to photochromic articles and to preparation thereof from organic polymerisable compositions. A process for manufacture of a photochromic polymeric article comprising: providing a fluid polymerisable composition; subjecting the fluid polymerisable composition to a first curing step to provide a solid article of intermediate hardness; contacting the solid article of intermediate hardness with a photochromic substance; and subjecting the solid article of intermediate hardness to a further curing step to increase the hardness and provide a polymeric article imbibed with the photochromic substance.