Novel photochromic 2,2´-bithiophene azo dyes

• Author(s): Coelho, Paulo J. ; Carvalho, Luís H. Melo de ; Moura, João C. V. P. ; Raposo, M. Manuela M.
• Date: 2009
• Persistent ID: http://hdl.handle.net/1822/10647
• Origin: RepositóriUM - Universidade do Minho
• Subject(s): Photochromism; Heterocyclic azo dyes; Synthesis; Azo coupling; Bithiophene; Azo dyes; UV-Visible spectroscopy
• Document Type: Article
• Language: English

Description

The photochromic behaviour of two series of 2,2’-bithiophene azo dyes in THF solutions was studied. The photochromic properties and colour constancy were strongly dependent on the substitution pattern of the dyes. Under visible irradiation (> 420 nm) while some dyes exhibited a significant change in the colour intensity others exhibited an almost stable absorption. The photokinetic parameters of these systems are described.