Lithia-alumina-silica containing glass compositions and glasses suitable for chemical tempering and articles made using the chemically tempered glass

A method of chemically strengthening a glass piece, comprising the steps of:

• providing a glass piece having a predetermined shape and thickness and a composition according to claim 1, wherein the glass piece has at least one of the following properties:
• (a) a log 10 viscosity temperature of at least 1280° F. (694° C.) and (b) a liquidus temperature of at least 2350° F. (1288° C.);
• submerging the glass piece in a molten sodium nitrate bath heated to a temperature of greater than 300° F. for at least 8 hours to provide the glass piece with a case depth in the range of 7 to 16.5 mils, and
• removing the glass piece from the bath.

A method of chemically strengthening a glass piece, comprising the steps of:

• providing a glass piece having a predetermined shape and thickness and a composition comprising:
• Ingredient
• Percent by weight
• SiO2
• 60 to 75;
• Al2O3
• 18 to 28;
• Li2O
• 3 to 9;
• Na2O
• 0 to 3;
• K2O
• 0 to 0.5;
• CaO
• 0 to 3;
• MgO
• 0 to 3;
• SO3
• 0 to 0.20;
• Total iron expressed as Fe2O3
• 0 to 1.25;
• ZrO2
• 0 to 3;
• Total tin expressed as SnO2
• 0 to 0.70;
• TiO2
• 0 to 5;
• P2O5
• 0 to 1.75;
• ZnO
• 0 to 1.25;
• and
• B2O3
• 0 to 1.75;
• where CaO+MgO is 0 to 6 wt %, Al2O3+Zr02 is 18 to 28 wt %, and Na2O+K20 is 0.05 to 3.00 wt %, wherein the glass piece has a log 10 viscosity temperature of at least 1413° F. (767° C.) and a liquidus temperature of at least 2435° F. (1335° C.);
• submerging the glass piece in a molten sodium nitrate bath heated to a temperature of greater than 300° F. for at least 8 hours to provide the glass piece with a case depth in the range of 7 to 16.5 mils, and
• removing the glass piece from the bath.