Fabrication of glasses with low softening temperatures for mold-processing by ion-exchange

Abstract

Glasses having a low softening temperature are desired for compression molding techniques in order to lengthen the mold life. The final goal of this research is to obtain glasses, which are suitable for the precise molding in order to fabricate micro- to submicro-structures on the glass surfaces, utilizing the ion-exchange technique, which lowers the softening temperature of only the surface regions of the glasses. We examined variations in optical and thermal properties of a soda-lime silicate glass after ion-exchange in AgNO 3-NaNO3 molten salts under various conditions. The glass transition and softening temperatures were lowered after the ion-exchange by 80 K and 70 K, respectively. Molding tests were demonstrated for the ion-exchanged glasses using a glassy carbon mold having a one-dimensional periodical structure of 500 nm in frequency and 350 nm in depth within the area of 6 x 6 mm 2. It was found that the structure was successfully transferred on a part of the surface of the ion-exchanged glass at a lower temperature than that for the glass before ion-exchange. ©2008 The Ceramic Society of Japan. All rights reserved.