Synthesis and characterization of photochromic homopolymer/copolymer

✍ Scribed by Bharat B. Mistry; Ranjan G. Patel; Vithal S. Patel

• Publisher: John Wiley and Sons
• Year: 1997
• Tongue: English
• Weight: 234 KB
• Volume: 64
• Category: Article
• ISSN: 0021-8995
• DOI: 10.1002/(sici)1097-4628(19970502)64:5<841::aid-app3>3.0.co;2-p

✦ Synopsis

Photochromic spiropyran homopolymer/copolymers have been prepared by radical polymerization of 5-acrylamino-1,3,3-trimethylindolino-6 -nitro-8-methoxy spiropyran using different vinyl monomers such as methyl methacrylate, methyl acrylate, and styrene. The polymerization was carried out at 80ЊC in dimethylformamide using a,a-azobisisobutyronitrile as initiator. The polymers have been characterized by viscometry, gel permeation chromatography, thermogravimetric analysis, and infrared spectroscopy. The kinetics of photochromic behavior have been investigated by preparing a film of one copolymer blended with poly(methyl methacrylate). This film, on exposure to sunlight or suitable wavelength, showed a very strong photochromic effect. The decoloration reaction kinetics follow a first-order relationship. The duration for return of the color depends upon the intensity of incident light, ambient temperature, moisture content, and thermal treatment of the film.