Color, light, spectroscopy, and reactions

Photochromism, fluorogenic probes, and reactions to educate the public on color, light, spectroscopy and reactions will be demonstrated. The demonstration is based on solutions and coated films with spiropyran (SP) isomers. The colorless solution (SP) changes to blue, and red upon UV irradiation in different solvents, corresponding to formation of merocyanine (ME). ME is fluorescent, which allows us to visualize the reaction kinetics. Disappearance of the blue/red color corresponds to the reverse reaction from ME to SP, occurs at room temperature in daylight varied from several minutes to tens of minutes. The conversion from ME to SP could be accelerated under red light irradiation. The light involved reactions and reaction rates/kinetics will thus be visualized.