General Electric Company

Mohan Rajaram

Curtis E Scott

Joseph A Shrawder

Frederic F Ahlgren

Matthew J Curran

Stanley M Antczak

Victor Lien Lou

A synthetic fused silica composition comprising silica and aluminum, wherein said aluminum is generally present in at least 7 parts per million and the composition has a viscosity of at least 10,poise.

Viscosity tailoring of fused silica

A metal halide or mercury lamp including an arc tube comprised of a glass composition consisting essentially of at least 90 weight percent SiO.sub.2 and including between about 10 and 1000 parts per million of a trivalent element slected from the group consisting of Pr, Nd, Pm, Sm, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Ac, Th, Pa, U, Np, Pu, Am, Cm, Bk, Cf, Es, Fm, Md, No, Lr, Unq, Unp, Ga, and mixtures thereof such that the viscosity of the glass composition is greater than 10.sup.14.5 poise at 1100.degree. C.

Doped silica glass

An opaque silica comprises silica and at least one second phase solid material. The at least one second phase solid material is essentially uniformly dispersed in the silica. A cut surface formed through the silica is free from surface defects since the at least one second phase solid material forms an opaque silica that is free from porosity.

Opaque silica composition

A sodium containing lamp constructed to include of a fused quartz or fused silica arc chamber wherein the fused quartz and/or fused silica contains less than about 0.05 parts per million sodium. The arc chamber of the invention demonstrates a resistance to sodium diffusion resulting in a longer lived lamp with excellent color maintenance.

Sodium halide discharge lamp

A glass composition, particularly well suited for use in constructing sodium containing lamp envelopes. The glass composition is comprised of silica doped with yttrium and/or cesium, preferably in combination aluminum.

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Mentor, OH, United States of America

Mohan Rajaram