Fabircation And Photochromic Properties Of Pyrazolone/polymer (HPMC, PVA) Composite Film

Organic photochromic compounds have attracted considerable interest because of theirpotential applications in optical storage media, non-linear optical devices，optical switchingdevices and information processors. Pyrazolones are an important class of organicphotochromic compounds which exhibit reversible photochromic properties in the solid state.But the system is consist of small organic molecules, which is not easy to produce a device.From the point of view of practical, organic photochromic materials to meet the applicationof high-density information storage and optical switches, which shold be in film, fiber, flake,etc. However, the polymer material is one of the most widely used materials, because ofwhich has a good and easy processing, easy molding and film forming, etc. In order to makethe photochromic compounds has more advantages in device manufacturing, thepyrazolone/polymer composite films have been fabricated by physical doping. They havewell-photochromic properties. The main reseach contents are as follows:1. Based on our previous study, we take three pyrazolone which have goodphotochromism and we select good water-soluble polymers: hydroxypropyl methyl cellulose(HPMC) or polyvinyl alcohol (PVA) as a matrix. We fabricated pyrazolone/polymercomposite film by physical doping. The composite film shows well photochromic reaction.2. The photochromic properties and mechanism of pyrazolone/polymer composite filmhave been carefully investigated by UV-vis absorption, fluorescence emission spectra andRaman scattering spectra. The surface morphology characteristics of composite film werefurther studied with scanning electron microscope. The results show that: The composite filmshow well-reversible photochromic reaction; organic photochromic materials can evenly bedispersed to polymer matrix; the photochromic behavior, thermally fade behavior andphotochromic mechanism of composite film are consistent with the pure compound; the photochromic mechanism of composite film is also from enol-form to keto-form byphotoinduced conversion.