Method for manufacturing a single crystal according to a CZ method, including: pre-examining a correlation between an Al/Li ratio in a quartz raw material powder used for producing the quartz crucible, a use time of the crucible, a devitrification ratio at the use time, and occurrence or nonoccurrence of melt leakage attributable to the devitrification part; setting a range of the devitrification ratio of the quartz crucible in order not to generate the melt leakage, and determining a maximum use time of the quartz crucible according to the Al/Li ratio so as to fall within the set range of the ratio, on the basis of the correlation; and growing the single crystal by using the quartz crucible in the range of the maximum use time. This provides a manufacturing method which can efficiently use a quartz crucible to grow a single crystal while preventing occurrence of melt leakage.

A low cost method for producing a mechanically and thermally stable composite body containing a first layer of a material with a high silicic acid content and an additional component connected to a second layer of a material with a high silicic acid content and an additional component in a second concentration differina from the first concentration is provided. The method involves (a) preparing a first slurry layer having a free surface using a first shirt mass containing SiO.sub.2 particles and an additional component dispersed in a first dispersing agent, (b) providing a second slurry mass containing SiO.sub.2 particles and an additional component in a second concentration dispersed in a second dispersing agent, (c) forming a composite-body intermediate product by applying the second slurry mass to the free surface of the first slurry layer, and (d) heating the composite-body intermediate product while forming the composite body.

Ultralow expansion titania-silica glass. The glass has high hydroxyl content and optionally include one or more dopants. Representative optional dopants include boron, alkali elements, alkaline earth elements or metals such as Nb, Ta, Al, Mn, Sn Cu and Sn. The glass is prepared by a process that includes steam consolidation to increase the hydroxyl content. The high hydroxyl content or combination of dopant(s) and high hydroxyl content lowers the fictive temperature of the glass to provide a glass having a very low coefficient of thermal expansion (CTE), low fictive temperature (T.sub.f), and low expansivity slope.

A glass composition is provided including greater than or equal to 60 mol % to less than or equal to 75 mol % SiO.sub.2; greater than or equal to 10 mol % to less than or equal to 20 mol % Al.sub.2O.sub.3; greater than or equal to 5 mol % to less than or equal to 20 mol % Li.sub.2O; greater than or equal to 5 mol % to less than or equal to 15 mol % Na.sub.2O; greater than 0 mol % to less than or equal to 1 mol % K.sub.2O; greater than 0 mol % to less than or equal to 8 mol % MgO; and greater than or equal to 0.0001 mol % to less than or equal to 0.01 mol % Au. The glass composition may be fusion formed to produce a glass-based article. The glass-based article may be colored.

This glass material is formed from silica glass and includes a Group 14 element. The glass material includes an element X that encompasses tin and/or lead, as tetravalent ions X.sup.4+ and divalent ions X.sup.2+.

A method for manufacturing low-emissivity easy-clean glass and the resulting low-emissivity easy-clean glass and low-emissivity easy-clean composite glass. The method involves using RF (Radio Frequency) sputtering of a silicon oxide target while simultaneously introducing nitrogen gas, and simultaneously using DC (Direct Current) sputtering of a silver target to co-deposit nitrogen-doped silicon oxide silver (Si, O, N: Ag) on a clear glass substrate. This low-emissivity easy-clean glass can avoid oxidation issues, improve conductivity, hardness, water contact angle, and reduce hemispherical emissivity.