Synthesis and characterization of polyesters containing fluorescein dye units

Low molecular weight polyesters containing fluorescein units in their backbones were successfully synthesized. These fluorescent polymers showed a high solubility in most of the common organic solvents. The onset degradation temperatures of the polymers were greater than that of fluorescein. The glass transition temperatures were in the range 126-194 °C. The bathochromic fluorescence emissions in organic solutions at high concentrations, which resulted from the aggregation of fluorescein moieties, were prohibited by protecting the OH end groups with benzoyl groups. The polymer powders exhibited a maximum photoluminescence intensity at about 580 nm.