Photophysical properties of commercial red dyes in polymer films

A fluorescence study was conducted on commercial dyes (squaraines; triphenylmethane dyes; porphyrins and chlorins) in thin films of polyvinyl alcohol (PVA), poly (methyl methacrylate) (PMMA) and Hival 5108, a commercial polystyrene (PS) from Ashland. Fluorescence quantum yields were measured for dye–polymer system and compared to liquid- and solid-phase media values. All dyes were found to have fluorescent yields and stabilities that were dependent on the polymer film material. Squaraine dyes, SQ3 and OH-SQ, exhibited the highest quantum yields (Φf) when miscible in polymer films, reaching values as high as 0.89 in PS and 0.79 in PMMA. Acceptable Φf at wavelengths higher than 650 nm were observed for SQ3, OH-SQ, TPP and PP-IX-DME. Moreover, fluorescence decay was measured after 240 s of CW irradiation for all the dye–polymer films studied.