Chlorin in Polystyrene: A Polymeric Material for Reversible Photochemical Hole Burning Storage
Original Publication Date: 1980-Jan-01
Included in the Prior Art Database: 2005-Feb-13
Chlorin (H(2)PH(2), which is obtained by reducing porphin to its dihydro derivative, has an electronic transition at 637 nm (versus 612 nm in H(2)P). Dissolving chlorin together with a polymer in a solvent, such as methylene chloride or toluene, and allowing the solvent to evaporate slowly produces pale green films of reasonably good optical quality. In polystyrene the inhomogeneous bandwidth at 637 nm is much broader (by a factor of approximately 100) than in crystalline matrices. Irradiation into this band at liquid helium temperatures leads to narrow hole-burning, accompanied by the formation of a photoproduct band at approximately 1600 cu cm higher energy. This photoproduct absorbs at approximately 577 nm; and again narrow holes can be burned into it, transferring intensity to the original band at 637 nm.