Optical properties and Judd-Ofelt intensity parameters of Eu\pmb{$^{3 + }$} in PMMA:PAAc copolymer samples

Abstract

Eu$^{3 + }$-activated PMMA:PAAc copolymers samples with different concentrations of Eu$^{3 + }$ ions were prepared and the spectroscopic properties investigated. The mass density, refractive index, UV--Visible absorption and emission spectra and fluorescence decay times were experimentally obtained. These data were used with the Judd-Ofelt theory to calculate the oscillator strengths, the spontaneous emission probabilities and the branching ratios as a function of the europium content; the Eu concentration was varied in the range from 0.1 to 3 mol %. The europium ions affect the polymerization mechanism since their presence produced a steric effect, which reduces the reactivity of the acrylic acid. We analyzed the optical interaction mechanism between the RE$^{3+}$ and the polymeric matrix, which is of radiative type.