SPECTROSCOPIC PROPERTIES OF TRIVALENT EUROPIUM AND TERBIUM IONS IN MODIFICATED POLYETHYLENE PHTHALATE WITH AZA-AROMATIC ACIDS

We have measured the emission spectra and lifetimes for Eu(III) and Tb (III) ions in polyethylene phthalate doped with some N-hetero-aromatic s acids, which were pyrazine-2-carboxylic, pyridine-2-carboxylic, pyri dine-3-carboxylic acids and amine-3-substituted acids. From the result s we have found that pyrazine 2-carboxylic acid enhances both europium and terbium luminescence, while the other acids increase the polymer luminescence. This points out that these acids are less effective in t ransferring energy to Eu(III) and Tb(III) excited states than the firs t one.