BK7 optical glass

Product Information Low transformation temperatures suitable for precision molding Precision molding is one of the state-of-the-art-technologies for the volume production of complex lenses (e. g. aspheres), for various applications. SCHOTT offers several optical glasses specifically developed for precision molding – the low Tg glasses, such as P-SF68, P-SK57Q1, P-SK58A and P-BK7. Low Tg glasses have a glass transformation temperature suitable for precision molding and a special glass composition to decrease the tendency for devitrification and to reduce the reaction with mold materials within the molding temperature range. During precision glass molding, a polished or fire polished preform is shaped into a final geometry, while conserving its surface quality. The typical temperature range for the molding process is between 500 °C and 700 °C, enabling the extension of the operating lifetime of the mold material and a significant time reduction of the press process. SCHOTT low Tg glasses are provided in the form of optical glass rods as well as ball lenses in different formats. Advantages • Low transformation temperatures, mostly below 550 °C, to increase lifetime of molds and to reduce process time • Low tendency for chemical interaction between glass constituents and mold materials within the molding temperature range • Tight optical tolerance • Wide range of dimensions • Various forms of supply • Application support