Effect of glass composition on silver-incorporation into aluminoborosilicate glasses through a staining process
- PDF / 663,282 Bytes
- 7 Pages / 584.957 x 782.986 pts Page_size
- 93 Downloads / 244 Views
Takashi Wakasugi and Kohei Kadonoa) Division of Chemistry and Materials Technology, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585, Japan (Received 17 August 2009; accepted 16 December 2009)
To fabricate graded-index optical elements by silver staining, we investigated the behavior of ion incorporation in aluminoborosilicate glasses, in which the contents of Al2O3 and Na2O were the same (in mol%). The amount of silver incorporated into the aluminoborosilicate glasses by the staining at 320 C for 12 h was 5 to 10 times larger than that incorporated into the soda-lime silicate and borosilicate glasses. The diffusion depth of the incorporated silver ions was approximately 80 mm, which was also much deeper than that of the soda-lime silicate and borosilicate glasses. The coloration of the glasses was suppressed, particularly for the glass with the low content of Na2O. The concentration of the incorporated silver ions at the glass surface was 2 1021 atom/cm3 for the 37.5SiO225Al2O325Na2O12.5B2O3 glass, corresponding to the replacement of sodium ions (20%). The refractive indices near the stained surfaces increased by 0.04 to 0.06. These values were comparable with those of the soda-lime silicate and borosilicate glasses.
I. INTRODUCTION
Staining is a well known, glass-coloring technique that has been used to color and mark glassware. In the staining process, mixtures of inorganic compounds of silver or copper, organic resins, and organic solvents, called as stain, are applied on glasses, and the glasses are then heat-treated. During the heat treatment, silver or copper ions are incorporated into the glass surfaces and reduced to atoms, and then the atoms precipitate to form nanoparticles.1–4 Because the nanoparticles have strong absorption in the visible region, the glasses are colored. The incorporation of the ions by the staining process is regarded as a similar reaction to the ion exchange, which is usually performed in molten salts.1–4 Therefore, the coloration as well as the refractive index change should be induced if the polarizability of the exchanged ions is different. Thus, the staining process can be used to fabricate graded-index optical elements. We have demonstrated that optical waveguides are prepared by the staining without any coloration in the visible to near-infrared region, under an appropriate heat-treatment condition.5 a)
Address all correspondence to this author. e-mail: [email protected] DOI: 10.1557/JMR.2010.0086 J. Mater. Res., Vol. 25, No. 4, Apr 2010
http://journals.cambridge.org
Downloaded: 14 Mar 2015
In the case of fabrication for the graded-index optical elements, the glass substrates should have high transparency in the visible to near-infrared region before and after ion doping. It is preferred that the incorporated ions have sufficiently high mobility in the glass substrates and high polarizability. This effect causes the high gradient in the refractive index to quickly form in the substrates. Silver ions are often used for ion exchange in molten salt
Data Loading...
