Sodalite-related glass compositions for production of photochromic and fluorescent articles

• US 3,923,529 A
• Filed: 01/10/1975
• Issued: 12/02/1975
• Est. Priority Date: 01/10/1975
• Status: Expired due to Term

• Current Assignee: George H. Beall, Loris G. Sawchuk, Roger J. Araujo
• Original Assignee: George H. Beall, Loris G. Sawchuk, Roger J. Araujo
• Inventors: Araujo, Roger J., Beall, George H., Sawchuk, Loris G.
• Primary Examiner(s): McCarthy, Helen M.
• Application Number:
  US05/540,169
• Time in Patent Office: 326 Days
• Field of Search: 106/DIG.6,39.6,39.7,47,52,54
• US Class Current: 501/42
• CPC Class Codes: C03C 10/00 Devitrified glass ceramics, i.e. glass ceramics having a crystalline phase dispersed in a glassy phase and constituting at least 50% by weight of the total composition
• CPC Class Codes: C03C 3/062 with less than 40% silica by weight
• CPC Class Codes: C03C 3/064 containing boron
• CPC Class Codes: C03C 3/112 containing fluorine
• CPC Class Codes: C03C 3/23 containing halogen and at least one oxide, e.g. oxide of boron
• CPC Class Codes: C03C 4/065 for silver-halide free photochromic glass
• CPC Class Codes: C03C 4/12 for luminescent glass; for fluorescent glass

Abstract

Compositions comprising sodium oxide and optionally other alkali metal oxides, a glass network-forming oxide such as SiO2 or GeO2, a modifying oxide such as Al2O3 or Ga2O3, a halogen such as Cl or F, and an electron donor constituent such as sulfur, selenium or tellurium, are melted to form glasses which may be reversibly photochromic, and are thermally crystallized to form glassceramics comprising sodalite or analogous crystal phases which are also reversibly photochromic. The glasses and glass-ceramics may also exhibit induced fluorescence in the activated (darkened) state.

Claims

1. A GLASS COMPOSITION USEFUL FOR THE PRODUCTION OF PHOTOCHROMIC GLASS AND GLASS-CERAMIC ARTICLES WHICH CONSISTS ESSENTIALLY OF, IN WEIGHT PERCENT AS CALCULATED FROM THE BATCH, ABOUT 17-34% TOTAL OF ALKALI METAL OXIDES, ESSENTIALLY INCLUDING NA2O, SELECTED IN THE INDICATED PROPORTION FROM THE GROUP CONSISTING OF 12-33% NA2O, 0-20% K2O, AND 0-7% CS2O;

17-33% TOTAL OF MODIFYING OXIDES SELECTED FROM THE GROUP CONSISTING OF AL2O3 AND GA2O3;

22-54% TOTAL OF NETWORK-FORMING OXIDES SELECTED IN AMOUNTS NOT EXCEEDING THE INDICATED PROPORTIONS FROM THE GROUP CONSISTING OF UP TO 41% SIO2 AND UP TO 54% GEO2;

2.5-30% TOTAL OF HALOGEN SELECTED IN AMOUNTS NOT EXCEEDING THE INDICATED PROPORTIONS FROM THE GROUP CONSISTING OF UP TO 9% F AND UP TO 30% CL;

AND 1-10% TOTAL OF CONSTITUENTS SELECTED FROM THE GROUP CONSISTING OF SO3, SEO2 AND TE.

2. A composition in accordance with claim 1 which further contains 0-15% B2O3, and 0-10% total of oxides selected from the group consisting of CdO and ZnO.

3. A glass composition in accordance with claim 1 wherein the selected halogen is fluorine.

4. A glass composition in accordance with claim 3 consisting essentially, in weight percent as calculated from the batch, of about 31-35% SiO2, 26-30% Al2O3, 26-30% Na2O, 0-10% B2O3, 4-7% F and 1-5% SO3.