Structural changes of Ag + –Na + ion exchanged soda-lime glasses investigated by scanning electron microscopy and infrared reﬂectivity F. Catan a , D. De Sousa Meneses b,c, * , J.P. Blondeau a , L. Allam a a LESI, 21 Rue Loigny la Bataille, 28000 Chartres, France b CNRS-CRMHT, 1D, Avenue de la Recherche Scientiﬁque, F 45071 Orle ´ans cedex 2, France c Polytech’ Orle ´ans, 8, Rue Le ´onard de Vinci, F 45072 Orle ´ans cedex 2, France Received 16 November 2006; received in revised form 29 June 2007 Available online 26 November 2007 Abstract The combination of infrared spectroscopy and scanning electron microscopy allowed the monitoring of the structural changes of a soda-lime glass submitted to increasing durations of Ag + –Na + ion exchange in a molten salt bath at 350 °C. Both techniques show an insertion of silver ions in the glass structure that is about 10% higher than the departure of sodium ions. The electro neutrality of the compounds is preserved with local alterations which lead to a higher degree of depolymerization of the silicate network. During the exchange process only sodium leaves the matrix and its content does not go beyond a threshold of about 50% of the initial content. Ó 2007 Elsevier B.V. All rights reserved. PACS: 61.43.Fs; 78.30.j Keywords: Chemical properties; Ion exchange; Microscopy; Scanning electron microscopy; Oxide glasses; Alkali silicates 1. Introduction The ion exchange technique between a glass and a mol- ten salt bath has been applied to develop special glasses with high functionality such as gradient index rod [1], pla- nar waveguides [2,3] and fabrication of passive integrated optical devices [4,5]. Typically the exchange is performed by placing a sodium silicate glass into a molten salt bath, from where one type of ion, e.g. Ag + ion (one of the most often used [6]) diﬀuses inside the glass and replaces another type of ion, e.g. Na + ion. It was found that some structural alterations are induced during the Ag + –Na + ion exchange in silicate glasses [7,8]. This network evolution, which is corroborated by other analyses such as infrared spectros- copy, Si-MAS NMR or O1s photoelectron spectra [9], needs to be understood from a fundamental point of view and for a better mastering of the technique of elaboration. The main goal of this paper is, by submitting a commer- cial silicate glass to several durations of treatment, to char- acterize and improve our knowledge of the ion exchange process. A detailed characterization of the glass composi- tion and structure is achieved by using scanning electron microscopy (SEM) and infrared spectroscopy (IR). SEM is coupled with X-ray microanalysis to derive the time evo- lution of the Ag + –Na + ion exchange process. 2. Experimental 2.1. Sample preparation Samples used in this experiment were prepared by the Ag + –Na + ion exchange technique with a commercial 0022-3093/$ - see front matter Ó 2007 Elsevier B.V. All rights reserved. doi:10.1016/j.jnoncrysol.2007.08.071 * Corresponding author. Address. Centre de Recherche sur les Mate ´ri- aux a ` Haute Tempe ´rature CRMHT-CNRS UPR4212, 1D, Avenue de la Recherche Scientiﬁque, F 45071 Orle ´ans cedex 2, France. Tel.: +33 (0) 238 63 81 03; fax: +33 (0) 238 25 55 34. E-mail address: desousa@cnrs-orleans.fr (D. De Sousa Meneses). www.elsevier.com/locate/jnoncrysol Available online at www.sciencedirect.com Journal of Non-Crystalline Solids 354 (2008) 1026–1031