Impregnation of fluorescence dyes into polymer optical fiber using carbon dioxide fluid

Abstract

In this work, subcritical levels of carbon dioxide fluids have been successfully used to prepare polymethyl methacrylate (PMMA) polymer optical fibers (POFs) with rhodamine dyes. The solubility of rhodamine dyes in the carbon dioxide fluids with and without cosolvent was measured at 293 and 313 K over the pressure range 8-24 MPa. Impregnation experiments were carried out from 5.0 up to 20 MPa, and at 283 to 323K. The effects of experimental factors (cosolvent, temperature, pressure and impregnation time) were then investigated. Distributions of dyes in POFs were observed by microscope, and the optic characteristics of the POFs were determined from the measurement of fluorescence spectrum, which was pumped at 532 nm with a Nd : YAG laser. Moreover, the results clearly indicate that compared with the conventional drop method, the impregnation using CO₂ fluids does not affect the fluorescence performance of the rhodamine dyes.