LED switching of spiropyran-doped polymer films

Spiropyrans are a well-known family of photochromic compounds that switch from uncoloured to highly coloured upon exposure to UV light with potential applications such as optical switches and memory storage devices. Typically the light sources used for controlling the state of the spiropyran are high power sources such as mercury lamps and lasers. Here we report the use of low power light emitting diodes (LEDs) to actuate the colour change in spiropyran-doped polymer films. The use of LEDs as an effective means of switching the dye expands the possible applications of these types of photochromic materials.