Abstract: A sensor according to the invention includes a surface having a sensing material that is responsive to a change in an environmental condition when illuminated. An illumination source is positioned to illuminate the surface. A receiver is positioned to receive light emanating from the surface; and a detector detects a change in light received at the receiver.

Abstract: A polymeric material which exhibits an optically detectable response to changes in pressure. The material includes an elastomer selected from the group of a polyurethane, a polyacrylate, and a silicone, in combination with a photochemical system. The photochemical system may be in the form of an exciplex or a fluorescence resonance energy transfer. Both photochemical systems are reversible processes. Synthesis of the elastomer and the photochemical system produce a material which forms an excited charge transfer complex when subject to an increase in pressure and a less excited charge transfer complex as pressure is lowered.