EXCITED-STATE ABSORPTION IN THE GAHNITE GLASS-CERAMICS AND ITS PARENTGLASS DOPED WITH CHROMIUM

We report on comparison of the basic spectroscopy and first of all exc ited state absorption (ESA) characteristics measured for the chromium doped pink gahnite glass ceramics and its green parent glass doped wit h chromium. The ESA spectrum of the ceramics is rather predictable and reveals peaks which can be ascribed to doublet-doublet transitions, t ypical for the Cr3+ ions in the high crystal field, and is additionall y affected by the ground state absorption bleaching. Unlike the cerami cs, the parent glass, being a low-field material, reveals quartet-quar tet ESA, typical for the Cr3+ ions in the low crystal field. The ESA s pectrum apart of chromium-related features and bleaching of the chromi um ground state absorption, is connected with other possible centers o f the host. Based on basic spectroscopic data we create configuration coordinate diagrams for both cases, predict the shape of the expected ESA spectra and compare them with measured ones. A reasonable agreemen t has been achieved. (C) 1998 Elsevier Science B.V. All rights reserve d.