Coloration behavior and variation in thermal properties of ag-doped glasses prepared by ion-exchange

Abstract

It has been reported that a sub-wavelength structure can be formed at the surface of glass, into which silver ions are incorporated through ion-exchange, by means of imprint molding at a lower temperature than softening temperature of the glass. In order to apply this technique to practical glass systems used in mold processing, we investigated ion-exchange behaviors, variation in softening temperature and optical transmission spectra after the ion-exchange and post-heat-treatment for various kinds of glasses. The results were discussed from the viewpoint of the glass composition and structure. The investigated glasses were soda-lime silicate, aluminosilicate, borosilicate, aluminoborosilicate, and fluoroaluminoborosilicate glasses. The amount of incorporated silver at the same ion-exchange condition was the highest for the aluminosilicate glass, and decreased in the order of aluminoborosilicate, soda-lime silicate, borosilicate, and fluoroaluminoborosilicate glasses. The lowering rate of softening temperature had a good correlation with the ion-exchange rate, i.e., molar fraction of Ag to total monovalent ions at the glass surface. For aluminosilicate and aluminoborosilicate glasses having no or little non-bridging oxygen, no coloration was occurred after the ion-exchange and post-heat-treatment although the absorption edge at the short wavelength side shifted to the near ultra violet region. Whereas the fluoride ions in fluoroaluminoborosilicate glass hindered the ionexchange, they suppressed the reduction Of Ag+ ions and the red-shift of the absorption edge. © 2010 The Society of Materials Science, Japan.