An additive manufacturing method includes heating a glass having a glass transition temperature (T.sub.g) of about 500 C. or less, flowing the heated glass through a nozzle onto a platform, and moving the nozzle relative to the platform while the heated glass is flowed through the nozzle onto the platform to form an object on the platform.

An additive manufacturing method includes heating a glass having a glass transition temperature (T.sub.g) of about 500 C. or less, flowing the heated glass through a nozzle onto a platform, and moving the nozzle relative to the platform while the heated glass is flowed through the nozzle onto the platform to form an object on the platform.

Alkali free fluorophosphate-based glass system that is highly radiation resistance (for example, they remain transparent and do not solarize before, during, and after application of high energy radiation of 10.sup.5 Rad or (1 kGy) or greater) and hence, reusable and further, when used with Ce provide a mechanism for determining the existence of radiation.

Alkali free fluorophosphate-based glass system that is highly radiation resistance (for example, they remain transparent and do not solarize before, during, and after application of high energy radiation of 10.sup.5 Rad or (1 kGy) or greater) and hence, reusable and further, when used with Ce provide a mechanism for determining the existence of radiation.

The present disclosure provides a device and a method with which flat glasses with particularly uniform thickness can be obtained. The methods are drawing methods in which a glass ribbon is drawn. In the method an aperture is used which allows a defined very small slit between the glass ribbon and the aperture also in the case of a change of the position of the glass ribbon.

The present disclosure provides a device and a method with which flat glasses with particularly uniform thickness can be obtained. The methods are drawing methods in which a glass ribbon is drawn. In the method an aperture is used which allows a defined very small slit between the glass ribbon and the aperture also in the case of a change of the position of the glass ribbon.

To provide an optical glass having the optical characteristics of a high refractive index and low dispersion, and moreover, which makes it possible to further reduce devitrification and which can be stably obtained, and a preform and an optical element using the same. The optical glass comprises, expressed in cation % (mol %), 17.0% to 42.0% of P.sup.5+, 7.0% to 30.0% of Al.sup.3+, more than 0% to 22.0% of Mg.sup.2+, more than 0% to 25.0% Ca.sup.2+, more than 0% to 30.0% of Sr.sup.2+, more than 0% to 35.0% Ba.sup.2+, and expressed in anion % (mol %), a content ratio of F.sup. of 37.0 to 64.0%, a content ratio of O.sup.2 of 36.0 to 63.0%, a refractive index (nd) of 1.48 to 1.58, and having an Abbe number (vd) of 70 to 88, and a liquidus temperature of 800 C. or less.

To provide an optical glass having the optical characteristics of a high refractive index and low dispersion, and moreover, which makes it possible to further reduce devitrification and which can be stably obtained, and a preform and an optical element using the same. The optical glass comprises, expressed in cation % (mol %), 17.0% to 42.0% of P.sup.5+, 7.0% to 30.0% of Al.sup.3+, more than 0% to 22.0% of Mg.sup.2+, more than 0% to 25.0% Ca.sup.2+, more than 0% to 30.0% of Sr.sup.2+, more than 0% to 35.0% Ba.sup.2+, and expressed in anion % (mol %), a content ratio of F.sup. of 37.0 to 64.0%, a content ratio of O.sup.2 of 36.0 to 63.0%, a refractive index (nd) of 1.48 to 1.58, and having an Abbe number (vd) of 70 to 88, and a liquidus temperature of 800 C. or less.

Provided is an etching method for a glass, including an etching step (S2) of immersing a glass (G) in an etching liquid (E) to subject the glass (G) to etching treatment. The etching step (S2) includes causing the etching liquid (E) to relatively flow with respect to a surface (MS) of the glass (G), to thereby subject the glass (G) to the etching treatment.

Provided is an etching method for a glass, including an etching step (S2) of immersing a glass (G) in an etching liquid (E) to subject the glass (G) to etching treatment. The etching step (S2) includes causing the etching liquid (E) to relatively flow with respect to a surface (MS) of the glass (G), to thereby subject the glass (G) to the etching treatment.