Abstract: Method and apparatus for non-destructively monitoring the thickness and uniformity of electrically conductive coatings (12) that have been deposited upon optical waveguide fibers (10). The monitoring may be performed while coated fiber (22) is at rest or while it is in motion. Physical contact with fiber (22) is not required. Monitoring is accomplished by feeding coated fibers (22) through an inductive coil (24) while simultaneously measuring an electrical value that is dependent upon the electrical resistance of conductive coating (10) then passing through inductive coil (24). The electrical value measured for a given section of coated fiber (22) becomes indicative of the coating thickness and uniformity of the coating about optical waveguide fiber (10) by correlating the electrical value measured with previously measured electrical values generated by coated fibers having coatings of known thicknesses and having no bald spots or other non-uniformities.

Abstract: Glass products such as glass lens elements are formed by an improved direct molding process at glass viscosities in the range of 10.sup.8 -10.sup.12 poises. Selected moldable alkali aluminofluorophosphate optical glasses are pressed to an optical surface finish in air utilizing an optically smooth titanium nitride molding surface, the surface being provided, for example, as a surface coating on a stainless steel mold or on a nickel chromium alloy mold supporting an electroless nickel base coating.

Abstract: The instant invention relates to the development of an embedment material suitable for use in heat treating glass castings to convert them into glass-ceramic articles, whereby the shrinkage customarily experienced resulting from densification of the casting during conversion to a glass-ceramic is minimized and sound glass-ceramic articles of tight dimensional tolerances can be produced. The inventive embedment materials will:(a) contain an inorganic component which is subject to an inversion accompanied with a large change in volume at a temperature below the set point of the glass-ceramic article;(b) demonstrate a coefficient of thermal expansion equal to or no more than about 40.times.10.sup.-7 /.degree.C.

Abstract: A process for the production of a gradient photochromic glass article comprising the selective over-nucleation of a limited portion of the article followed by a photochromic development heat treatment of the entire article, and the product of this process, are described.