Photosensitively opacifiable glass

Claim 1

A CLEAR, TRANSPARENT PHOTOSENSITIVE GLASS COMPRISING ESSENTIALLY 55% TO 75% SIO2, THE INDICATED PROPORTION OF AT LEAST ONE ALKALI METAL OXIDE SELECTED FROM THE GROUP CONSISTING OF UP TO 2% LI20, 5% TO 18% NAZ0, AND UP TO 13% K20, THE SELECTED ALKALI METAL OXIDE INCLUDING NA2O THE TOTAL ALKALI METAL OXIDE CONTENT BEING 12% TO 18%, 2% TO 12% AL203, 0.0001% TO 0.3% OF SILVER COMPUTED AS AGCL, 0.005% TO 0.5% CE02, 1.8% TO 3.0% OF ANALYTICALLY DETERMINED FLUORINE, AND THE INDICATED PROPORTION OF A HALOGEN SELECTED FROM THE GROUP CONSISTING OF 0.01% TO 0.2% OF ANALYTICALLY DETERMINED CHLORIDE 0.02 TO 0.4 % OF ANALYTICALLY DETERMINED BROMINE, AND 0.03% TO 0.6% OF ANALYTICALLY DETERMINED BROMINE, IODINE, THE ESSENTIAL CONSTITUENTS TOTALING AT LEAST 85%, SAID GLASS BEING THERMALLY OPACIFIABLE ONLY IN SUCH AREAS AS HAVE BEEN PREVIOUSLY EXPOSED TO SHORTWAVE-RADIATIONS.

Claim 3

THE METHOD OF MAKING A GLASS ARTICLE HAVING AN OPAQUE DESIGN FORMED WITHIN ITS MASS, WHICH INCLUDES THE STEPS OF EXPOSING TO SHORTWAVE RADIATIONS AT LEAST A PORTION OF AN ARTICLE FORMED FROM A CLEAR, TRANSPARENT GLASS CAPABLE OF BEING THERMALLY OPACIFIED ONLY IN SUCH AREAS AS HAVE BEEN PREVIOUSLY EXPOSED TO SHORT-WAVE RADIATIONS AND COMPRISING ESSENTIALLY 55% TO 75% SI02, THE INDICATED PROPORTION OF AT LEAST ONE ALKALI METAL OXIDE SELECTED FROM THE GROUP CONSISTING OF UP TO 2% LI20, 5% TO 18% NA20, AND UP TO 13% K20, THE SELECTED ALKALI METAL OXIDE INCLUDING NA20, THE TOTAL ALKALI METAL CONTENT BEING 12% TO 18%, 2% TO 12% AL203, 0.0001% TO 0.3% OF SILVER COMPUTED AS AGCL 0.005% TO 0.05% CE02, 1.8% TO 3.0% OF ANALYTICALLY DETERMINED FLUORINE, AND THE INDICATED PROPORTION OF A HALOGEN SELECTED FROM THE GROUP CONSISTING OF 0.01% TO 0.2% OF ANALYTICALLY DETERMINED CHLORINE, 0.02% TO 0.4% OF ANALYTICALLY DETERMINED BROMINE AND 0.03% TO 0.6% OF ANALYTICALLY DETERMINED IODINE, THE ESSENTIAL CONSTITUENTS TOTALING AT LEAST 85%, HEATING THE EXPOSED ARTICLE FOR A TIME AND AT A TEMPERATURE VARYING FROM ABOUT ONE MINUTE AT ABOUT 50* C. ABOVE THE SOFTENING POINT OF THE GLASS TO ABOUT ONE HOUR AT ABOUT 150* C. BELOW THE SOFTENING POINT OF THE GLASS, COOLING THE ARTICLE BELOW ABOUT 500* C., REHEATING THE ARTICLE TO A TEMPERATURE NOT LOWER THAN ABOUT 100* C. BELOW THE SOFTENING POINT OF THE GLASS UNTIL ITS EXPOSED PORTION DEVELOPS THE DESIRED DEGREE OF OPACITY, AND THEN COOLING THE ARTICLE TO ROOM TEMPERATURE.

Claim 4

THE METHOD OF MAKING A GLASS ARTICLE HAVING AN OPAQUE DESIGN FORMED WITHIN ITS MASS, WHICH INCLUDES THE STEPS OF EXPOSING TO SHORTWAVE RADIATIONS AT LEAST A PORTION OF AN ARTICLE FORMED FROM A CLEAR, TRANSPARENT GLASS CAPABLE OF BEING THERMALLY OPACIFIED ONLY IN SUCH AREAS AS HAVE BEEN PREVIOUSLY EXPOSED TO SHORT-WAVE RADIATIONS AND COMPRISING ESSENTIALLY 55% TO 75% SI02, THE INDICATED PROPORTION OF AT LEAST ONE ALKALI METAL OXIDE SELECTED FROM THE GROUP CONSISTING OF UP TO 2% LI20, 5% TO 18% NA20, AND UP TO 13% K20, THE SELECTED ALKALI METAL OXIDE INCLUDING NA20, THE TOTAL ALKALI METAL CONTENT BEING 12% TO 18%, 2% TO 12% AL203, 0.0001% TO 0.3% OF SILVER COMPUTED AS AGCL 0.005% TO 0.05% CE02, 1.8% TO 3.0% OF ANALYTICALLY DETERMINED FLUORINE, AND THE INDICATED PROPORTION OF A HALOGEN SELECTED FROM THE GROUP CONSISTING OF 0.01% TO 0.2% OF ANALYTICALLY DETERMINED CHLORINE, 0.02% TO 0.4% OF ANALYTICALLY DETERMINED BROMINE AND 0.03% TO 0.6% OF ANALYTICALLY DETERMINED IODINE, THE ESSENTIAL CONSTITUENTS TOTALING AT LEAST 85%, HEATING THE EXPOSED ARTICLE FOR A TIME AND AT A TEMPERATURE VARYING FROM ABOUT ONE MINUTE AT ABOUT 50* C. ABOVE THE SOFTENING POINT OF THE GLASS TO ABOUT ONE HOUR AT ABOUT 150* C. BELOW THE SOFTENING POINT OF THE GLASS, COOLING THE ARTICLE BELOW ABOUT 500* C., REHEATING THE ARTICLE TO A TEMPERATURE NOT LOWER THAN ABOUT 100* C. BELOW THE SOFTENING POINT OF THE GLASS UNTIL ITS EXPOSED PORTION DEVELOPS THE DESIRED DEGREE OF OPACITY, AND THEN COOLING THE ARTICLE TO ROOM TEMPERATURE.