A thermally tempered aluminosilicate glass-ceramic composition includes a crystalline phase and a residual glass phase, wherein the two phases form a system wherein the thermal expansion curve of the system has two distinct sections diverging from an inflection point temperature in the range of about 450° C. to about 600° C., and wherein the difference between coefficient of thermal expansion of the glass-ceramic below and above the inflection point is greater than about 4 ppm/° C.

Provided is a silica glass member which exhibits high optical transparency to vacuum ultraviolet light and has a low thermal expansion coefficient of 4.0−10.sup.−7/K or less at near room temperature, particularly a silica glass member which is suitable as a photomask substrate to be used in a double patterning exposure process using an ArF excimer laser (193 nm) as a light source. The silica glass member is used in a photolithography process using a vacuum ultraviolet light source, in which the fluorine concentration is 1 wt % or more and 5 wt % or less, and the thermal expansion coefficient at from 20° C. to 50° C. is 4.0×10.sup.−7/K or less.

The present invention provides for synthesizing high optical quality multicomponent chalcogenide glasses without refractive index perturbations due to striae, phase separation or crystal formation using a two-zone furnace and multiple fining steps. The top and bottom zones are initially heated to the same temperature, and then a temperature gradient is created between the top zone and the bottom zone. The fining and cooling phase is divided into multiple steps with multiple temperature holds.

The present disclosure is directed to glass spheroids and methods of making these spheroids that have significantly increased resilience to applied pressure and surface scratching. In addition, the present disclosure is directed to tailless Prince Rupert's Drops and methods of making tailless Prince Rupert's Drops.

The present invention provides for synthesizing high optical quality multicomponent chalcogenide glasses without refractive index perturbations due to striae, phase separation or crystal formation using a two-zone furnace and multiple fining steps. The top and bottom zones are initially heated to the same temperature, and then a temperature gradient is created between the top zone and the bottom zone. The fining and cooling phase is divided into multiple steps with multiple temperature holds.

The present invention provides for synthesizing high optical quality multicomponent chalcogenide glasses without refractive index perturbations due to striae, phase separation or crystal formation using a two-zone furnace and multiple fining steps. The top and bottom zones are initially heated to the same temperature, and then a temperature gradient is created between the top zone and the bottom zone. The fining and cooling phase is divided into multiple steps with multiple temperature holds.

A glass composition formed of glass frit including P.sub.2O.sub.5, TiO.sub.2 and group I-based oxide, wherein P.sub.2O.sub.5 is contained in an amount of 20 wt % to 30 wt % based on a total weight of the glass frit, wherein TiO.sub.2 is contained in an amount of 10 wt % to 20 wt % based on the total weight of the glass frit, and wherein the group I-based oxide is contained in an amount of 15 wt % to 30 wt % based on the total weight of the glass frit.

A glass composition formed of a glass frit including P.sub.2O.sub.5, SiO.sub.2, B.sub.2O.sub.3, Al.sub.2O.sub.3, ZrO.sub.2 and group I-based oxide, wherein P.sub.2O.sub.5 is contained in an amount of 20 wt % to 40 wt % based on a total weight of the glass frit, SiO.sub.2 is contained in an amount of to wt % to 30 wt % based on the total weight of the glass frit, B.sub.2O.sub.3 is contained in an amount of 3 wt % to 20 wt % based on the total weight of the glass frit, Al.sub.2O.sub.3 is contained in an amount of 7 to 24 wt % based on the total weight of the glass frit, ZrO.sub.2 is contained in an amount of 1 wt % to 7 wt % based on the total weight of the glass frit, and the group I-based oxide is contained in an amount of 7 wt % to 28 wt % based on the total weight of the glass frit.

The present disclosure is directed to glass spheroids and methods of making these spheroids that have significantly increased resilience to applied pressure and surface scratching. In addition, the present disclosure is directed to tailless Prince Rupert's Drops and methods of making tailless Prince Rupert's Drops.

Provided is a silica glass member which exhibits high optical transparency to vacuum ultraviolet light and has a low thermal expansion coefficient of 4.010.sup.7/K or less at near room temperature, particularly a silica glass member which is suitable as a photomask substrate to be used in a double patterning exposure process using an ArF excimer laser (193 nm) as a light source. The silica glass member is used in a photolithography process using a vacuum ultraviolet light source, in which the fluorine concentration is 1 wt % or more and 5 wt % or less, and the thermal expansion coefficient at from 20 C. to 50 C. is 4.010.sup.7/K or less.