Photochromic inks, dyes and masterbatches change their molecular structure and darken on exposure to specific types of light of sufficient intensity, most commonly ultraviolet (UV) radiation. In the absence of activating light they return to their clear state.
Photochromic dyes reversibly change colour upon exposure to ultraviolet light in the range of 300 to 360 nanometers.
Reversible photochromics are found in applications such as toys, cosmetics, nail varnish, ophthalmic and sunglass lenses, textile clothing and garments, footwear, packaging, glassware, ceramics, plastics, security, and industrial applications.
Photochromic dyes can be applied to fabrics through conventional printing and dyeing methods.
When used in textile ink printed onto clothing garments such as t shirts, the change to colour when exposed to sunlight occurs within 15 seconds or less, and returns to a near invisible clear shade after 5 minutes or less indoors when removed from the uv/sunlight.
Photochromic dyes can be mixed together to make an assortment of shades.
Photochromic masterbatch in pellet form can be dosed into injection moulded plastic items, or into plastic extrusion.
The strength of the colour change will increase as the plastic thickness increases.
Photochromic means ‘ability to change colour when exposed to sunlight’. Photochromic dyes generate dynamic reversible colour change under the sunlight or ultra violet (UV) light in the range of 300 to 360 nanometers. When placed into sunlight, or ultra violet rays, the molecular structure changes allowing the photochromic compound to turn into a darker colour. The effect is reversed when the light source fades. The speed at which the dyes fade back to become colourless depends on the ambient temperature, and chemical structure of the dye.