Abstract: A property-enhanced cover sheet, and methods for forming a property-enhanced cover sheet, for a portable electronic device are disclosed. A property-enhanced cover sheet is formed by thermoforming a glass sheet into a specified contour shape while modifying one or more properties of the glass. Other property-enhanced sheets can be formed by layering two or more glass sheets having different material properties, and then thermoforming the layered sheets into a required contour shape. Property enhancement for a cover sheet includes, hardness, scratch resistance, strength, elasticity, texture and the like.

Abstract: A method includes contacting a glass sheet with a forming surface to form a shaped glass article. An effective viscosity of the glass sheet during the contacting step is less than a contact viscosity of the glass sheet in contact with the forming surface during the contacting step.

Abstract: Provided is an article having a novel surface with a texture different from conventional kinds. The article having a metal oxide-containing coating provided by the present invention comprises a substrate and a metal oxide-containing coating provided to the substrate surface. The metal oxide-containing coating has a Vickers hardness of 350 or higher, a surface roughness Ra of 300 nm or less, and a 20° gloss value of 50 or higher.

Abstract: The invention is a method for structuring a flat substrate composed of glass material in the course of a viscous flow process. The glass flat substrate is joined to a surface of a flat substrate, which is preferably a semiconductor flat substrate, having at least one depression bounded by a circumferential edge located in the surface. In the course of a subsequent tempering process, glass material is changed to a viscous free-flowing state in which at least proportions of the free-flowing glass material of the flat substrate flow over the circumferential edge into the depression in the flat substrate.

Abstract: A system and method for coating glass gobs with a liquid-based lubricating dispersion during their drop to blank glass container molds which provides sufficient lubrication to the glass container molds without requiring swabbing of the glass container molds. The lubricating dispersion is sprayed onto hot glass gobs as they fall from the gob supply system prior to their distribution by the gob distribution system into blank molds. The lubricating dispersion coats the falling glass gobs to lubricate the glass gobs as well as the molds.

Abstract: A system and method for coating glass gobs with a liquid-based lubricating dispersion during their drop to blank glass container molds which provides sufficient lubrication to the glass container molds without requiring swabbing of the glass container molds. The lubricating dispersion is sprayed onto hot glass gobs as they fall from the gob supply system prior to their distribution by the gob distribution system into blank molds. The lubricating dispersion coats the falling glass gobs to lubricate the glass gobs as well as the molds.

Abstract: This disclosure features use of a paper or polymer film that includes a slip agent that can transfer to its surfaces. Once the paper or film is pressed against a glass sheet, this will leave a thin surface roughness of slip agent that can prevent or reduce glass surface scratches from other surfaces or particles during shipping or finishing (e.g., cutting to size, conveyance of glass), thereby improving the yield of glass shipments between glass forming plants and customers. The thin discontinuous layer of slip agent remaining on the glass surface can be washed off easily in subsequent washing processes. The paper or film can have the slip agent imbibed within the paper or coated on it as a surface member.

Abstract: A process for producing laminated by heating glass plates to a temperature close to a softening point to bend the glass plates includes a forming step for placing a plurality of glass plates 12 and 14 overlaid via a release agent on a ring mold 20 and bending the glass plates in a curved shape by gravity. In the forming step, at least two glass plates among the glass plates 12 and 14 have different plate thicknesses, the thinnest glass plate 14 has a plate thickness of less than 1.6 mm, and the plate thickness difference between the thinnest glass plate 14 and the thickest glass plate 12 is at least 0.5 mm. In the forming step, the glass plates 2 and 4 are placed on the ring mold 20 such that a thinner glass plate is disposed at a lower position.

Abstract: A method for forming a lubricant layer on the surface of a glass and a method for manufacturing a glass using the same prevents scratches from occurring at the surface of a glass and decreases corrosion of glass manufacturing equipment. The method for manufacturing a glass includes forming a glass, supplying SO2 gas and a SO2 gas oxidation catalyst to the glass under an oxidation environment to form a lubricant layer at the lower surface of the glass, and annealing the glass.

Abstract: A method of molding a synthetic silica glass molded body by accommodating a synthetic silica glass block in a mold provided with a pressing portion, and by pressing the block while heating, the method including: washing the synthetic silica glass block so that a concentration of copper which is present on the surface of the synthetic silica glass block is 2 ng/cm2 or less; heating high purity carbon powders with a content of copper and aluminium; heating the mold at a temperature condition of 1700° C. to 1900° C.; applying the powders before accommodating the block in the mold; and molding the block in a predetermined form by pressing the block while heating within a hold temperature range of 1500° C. to 1700° C., after accommodating the washed block in the mold.

Abstract: A source material, which is based on a glass, is arranged on a working surface of a mold substrate. The mold substrate is made of a single-crystalline material. A cavity is formed in the working surface. The source material is pressed against the mold substrate. During pressing a temperature of the source material and a force exerted on the source material are controlled to fluidify source material. The fluidified source material flows into the cavity. Re-solidified source material forms a glass piece with a protrusion extending into the cavity. After re-solidifying, the glass piece may be bonded to the mold substrate. On the glass piece, protrusions and cavities can be formed with slope angles less than 80 degrees, with different slope angles, with different depths and widths of 10 micrometers and more.

Abstract: Coated crucibles for holding molten material are disclosed. In some embodiments, the crucibles are used to prepare multicrystalline silicon ingots by a directional solidification process. Methods for preparing such crucibles and methods for preparing silicon ingots by use of such crucibles are also disclosed.

Abstract: Provided is a cutting method for a glass sheet, comprising radiating a laser beam to a cutting portion (C) of a glass sheet (G) having a thickness of 500 ?m or less to fuse the glass sheet (G), wherein a narrowest gap between fused end surfaces (Ga1 and Gb1) of the glass sheet (G), which face each other in the cutting portion (C), is managed to satisfy a relationship of 0.1?b/a?2, where “a” is a thickness of the glass sheet (G) and “b” is the narrowest gap.

Abstract: A glass container system comprises a glass container comprising a base defining a bottom of the container and a sidewall formed integrally with the base to define an interior space. A protuberance is formed integrally with the base where the protuberance extending beyond a side wall of the base. A lid is dimensioned such that the protuberance engages the lid such that the lid may be releasably secured to the base. A glass container prepared by a process comprising the steps of providing a mold defining a container having a base at a bottom of the mold cavity where the mold cavity comprises an undercut portion that defines a recess in the mold cavity; introducing molten glass to the mold; cooling the glass to cause the glass to shrink a sufficient amount that the protuberance recedes from the recess; and removing the container from the mold in a linear direction.

Abstract: A method of manufacturing a light-emitting device includes arranging a plate-shaped glass on a light-emitting element mounting surface of a substrate having a light-emitting element mounted thereon, arranging a metal thin plate on the plate-shaped glass so as to sandwich the plate-shaped glass between the substrate and the metal thin plate, placing the substrate, the plate-shaped glass and the metal thin plate between a first mold on a side of the substrate and a second mold on a side of the metal thin plate, hot-pressing the substrate, the plate-shaped glass and the metal thin plate by using the first mold and the second mold to seal the light-emitting element with the plate-shaped glass, and after cooling the plate-shaped glass, removing the thin plate adhered to the plate-shaped glass from the plate-shaped glass.

Abstract: A substrate protective film composed of chromium metal is formed on a molding surface of a mold base material composed of cemented carbide. The substrate protective film is oxidized by heat treatment or ion implantation, so that a surface protective film composed of chromium oxide is formed. A pair of molds having such a constitution are prepared. Softened glass is pressed between the surface protective films of the paired molds, so that optical glass elements are molded.

Abstract: The present invention relates to a method for manufacturing an ultra-thin glass substrate, the method including: a feeding step of feeding a preform for a glass substrate to a production line while being held; a heating step of heating the preform fed from the feeding step to a temperature around a softening point thereof; and a drawing step of drawing the preform that has softened in the heating step to form an ultra-thin glass substrate, in which the preform has been wound on a cylindrical first winding roll.

Abstract: Methods for edging optical articles comprising two main faces, at least one of which being coated with an outermost layer comprising fixing the optical article to a chuck with a holding pad that adheres to both the optical article and the chuck, wherein the surface of the holding pad contacting the optical comprises an adhesive material; and edging the optical article with an edging device; wherein prior to fixing the optical article to the chuck, at least one temporary layer of an organic material is formed onto said outermost layer of the optical article, the organic material of the temporary layer comprising at least one organic compound having a fluorinated functional moiety and at least one linking functional moiety capable of establishing at least one intermolecular bond or interaction with the adhesive material of the holding pad. Optical articles obtained via these methods.

Abstract: A titanium-containing oxide glass having a bulky form and substantially having a chemical composition represented by the formula: (M1)1-x(M2)x(Ti1-y1(M3)y1)y2O2 [wherein M1 represents an element selected from Ba, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Na and Ca; M2 represents at least one element selected from Mg, Ba, Ca, Sr, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Na, Sc, Y, Hf, Bi and Ag; M3 represents at least one element selected from V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Zr, Nb, Mo, Ru, Rh, Pd, Al, Si, P, Ga, Ge, In, Sn, Sb and Te; and x, y1, y2 and z satisfy the following requirements: 0?x?0.5, 0?y1<0.31, 1.4<y2<3.3, and 3.9<z<8.0, provided that x+y1?0 when M1 represents Ba, and y1?0 when both M1 and M2 represent Ba].

Abstract: A glass-shaping mold includes a steel base member, and a crystallized, machined layer, an intermediate layer and a mold-releasing layer which are sequentially formed on the base member. The machined layer is a layer of nickel alloy containing phosphorus. The intermediate layer is a layer formed of chromium, nickel, copper or cobalt. Alternatively, the intermediate layer is a layer of an alloy layer containing at least one of these elements. The mold-releasing layer is a layer of an alloy containing iridium and rhenium.

Abstract: The present invention provides a method of making a decorated multilayer glass structure using a single firing step that includes that use of a crystallizing glass enamel composition that contains ingredients to ensure the complete burnout of the organic portion of the composition upon firing and bending of a mated pair of glass sheets. A benefit of the composition is that when applied to one sheet of a mated pair of glass sheets, it burns out completely during firing and bending of the pair. The presence of high levels of oxidizers in the composition ensures a supply of oxygen to enable combustion of the organic vehicle while firing the glass sheets and prior to the sintering of the enamel composition to only one glass sheet in a mated pair of decorated or colored glass sheets.

Abstract: A substrate protective film composed of chromium metal is formed on a molding surface of a mold base material composed of cemented carbide. The substrate protective film is oxidized by heat treatment or ion implantation, so that a surface protective film composed of chromium oxide is formed. A pair of molds having such a constitution are prepared. Softened glass is pressed between the surface protective films of the paired molds, so that optical glass elements are molded.

Abstract: Disclosed is a method of manufacturing ultraprecise lenses, including aspherical lenses, not requiring grinding or polishing after press molding. The method comprises heating a glass material to a temperature corresponding to a glass viscosity of from 105 to 109 dPaS so that the glass material is softened, and press molding the glass material with the pressing molds which are heated to a temperature corresponding to a glass viscosity of from 108 to 1012 dPaS. Provided that the glass material is not heated to a temperature as high as that corresponding to a glass viscosity of 105 dPaS when the pressing mold is heated to a temperature corresponding to a glass viscosity of 108 and that the glass material is not heated to a temperature as low as that corresponding to a glass viscosity of 109 dPaS when the pressing mold is heated to a temperature corresponding to a glass viscosity of 1012 dPaS.

Abstract: The process according to the invention reduces the effort required to shape a glass piece. In this process a liquid glass piece is provided on a structured supporting surface of an electrically conducting base. A voltage is applied across the liquid glass piece by connecting a voltage source between a contact position on the liquid glass piece and the electrically conducting base. The apparatus for performing the process has an electrically conducting base on which the liquid glass piece is supported and a device for applying a voltage between a contact position on the liquid glass piece and the electrically conducting base.

Abstract: A method of manufacturing optical glass elements comprising the step of press molding a preformed glass material while in a heat-softened state, which material having a carbon film on a surface thereof, to transfer a molding surface of a pressing mold. The carbon film is less than or equal to 10 nm in thickness and is formed in such a manner that after press molding, a carbon film comprising at least two carbon atom layers in thickness is present on the surface of the optical glass element that has been molded by the molding surface. In the method of manufacturing glass elements, fusion between the glass material and the molding surfaces, flaws, and breach are prevented and fogging does not occur on the surface of the optical element obtained.

Abstract: A method of manufacturing a glass article comprises the steps of heat softening a glass material that has been preformed and press molding the glass material with a pressing mold. A glass material having a surface free energy of greater than or equal to 60 mJ/m2 is fed to the heat softening step, and then fed to the press molding step. Alternatively, a surface layer is formed on a preformed glass material having a surface free energy of greater than or equal to 60 mJ/m2, and then the preformed glass material is fed to the heat softening step and press molding step. Provided is a method of manufacturing glass products capable of easily obtaining glass products without surface fogging, clouding and cracking without large scale facility.

Abstract: A method of manufacturing a glass material for molding includes immersing a preformed glass material in an organic solution which contains an organic silicon-containing compound, an organic sulfur-containing compound, an organic fluorine-containing compound, or an organic nitrogen-containing compound to obtain the glass material which has a self-assembled film on a surface.

Abstract: The invention relates to a method and a device for reducing the adhesion tendency during the hot forming of a glass body, using at least two moulds, which are positioned on either side of the glass body and are brought into contact with the glass body at a temperature, at which the glass is deformable, whereby the moulds are configured with electrically conductive surfaces. The disadvantage of existing methods and devices is that the moulds have a tendency to adhere to the glass body to be formed and that the surface quality of the glass is impaired. The invention therefore discloses a method, according to which the conductive surfaces of the moulds that come into contact with the glass body are supplied with an alternating current. The device for carrying out said method has electrically conductive mould surfaces, which are connected to an alternating current source. This guarantees that a larger processing window is available as a result of the reduced adhesion tendency, i.e.

Abstract: Methods for press molding a glass body, especially for optical applications, without additional grinding and polishing steps are described. One method is performed with a press mold having an upper mold part, a lower mold part and, if necessary or desired, a ring. In order to improve the quality of the products, especially glass bodies of larger diameters, a voltage is applied across the upper mold part and the lower mold part when the glass body is within the press mold and a pressing force is applied to the glass body when the temperature of the glass body matches the temperature of the press mold. Alternatively, in another method the press mold is cooled after it reaches a predetermined temperature and the pressing force is applied to the glass body in the mold after exceeding the sticking temperature (T0).

Abstract: While avoiding the disadvantages of the screen printing technique employed until now, the invention provides a shaping tool (1) with a structured surface for creating structures on glass (2) which, in an economical way, makes it possible to form high-precision microstructures by local heating of the region of glass to be structured. The shaping tool (1) has a rolling cylinder (3) including a metal hollow cylinder (7) and a shaping sheet (8) secured in a surface contact to it, as well as a continuous shaft (5) for continuously driving the rolling cylinder (3) via drivers (4) coupled to the hollow cylinder (7). Between the shaft (5) and the hollow cylinder (7), an electric heater (6) for targeted local heating of the glass during structuring is disposed in an electrically insulated fashion. The electric heater (6) is advantageously thermally insulated from the shaft (5) with a ceramic cylinder (14).

Abstract: Disclosed is a method of manufacturing ultraprecise lenses, including aspherical lenses, not requiring grinding or polishing after press molding. The method comprises heating a glass material to a temperature corresponding to a glass viscosity of from 105 to 109 dPaS so that the glass material is softened, and press molding the glass material with the pressing molds which are heated to a temperature corresponding to a glass viscosity of from 108 to 1012 dPaS. Provided that the glass material is not heated to a temperature as high as that corresponding to a glass viscosity of 105 dPaS when the pressing mold is heated to a temperature corresponding to a glass viscosity of 108 and that the glass material is not heated to a temperature as low as that corresponding to a glass viscosity of 109 dPaS when the pressing mold is heated to a temperature corresponding to a glass viscosity of 1012 dPaS.

Abstract: A molten glass (8) is successively supplied from a nozzle (5) to a plurality of molding dies (7) and gradually cooled to form glass masses. Each glass mass is reheated in an air atmosphere to a temperature corresponding to a viscosity of 104-106 poises and press-molded by a mold to produce a press-molded product. The press-molded product is polished to form a final glass product.

Abstract: Disclosed is a mold including upper and lower molds for obtaining glass optical elements by press molding a glass molding material softened by heat, in which either one of the upper and lower molds is made of a ceramic matrix and the matrix has no surface hole having a diameter of 300 microns or more on the molding surface, and a method for manufacturing glass optical elements using the mold. For example, on the upper mold 21 and the lower mold 22, formed is a &bgr; type silicon carbide having a thickness that a molding surface can be reproduced by grinding and a density of 3.20 g/cm3 or more so as to include at least the molding surface facing a surface of the glass molding material G. The mold according to the invention can be reused even where pullouts occur from repetitive use.

Abstract: A silica glass forming method is a method of pressing a synthetic silica bulk having at least a set of opposed surfaces, on the surfaces under a high temperature condition by a presser, wherein an elastic member with permeability is placed between the presser and the surfaces of the synthetic silica bulk pressed by the presser and wherein the synthetic silica bulk is pressed through the elastic member by the presser. This method is able to reduce bubbles remaining inside the synthetic glass formed product after the forming to a sufficiently small amount. Therefore, it becomes feasible to provide the method that permits high-yield production of silica glasses with excellent optical characteristics.

Abstract: A new method is disclosed for producing thin plates by sintering a thin gel plate (e.g., silica) made using a sol-gel process, which substantially eliminates warpage of the plate during the sintering step. Sintering a sol-gel based silica plate to a dense glass typically causes significant shrinkage, and this can cause the plate to curl, especially around its edges. This phenomenon is referred to as warpage. In the method of the invention, the sintering step is performed while the gel plate is mounted on a support surface, separated by a thin layer of refractory powder. At the high sintering temperature, the powder partially fuses and sticks to both the gel plate and the support surface, which prevents non-uniform stresses in the gel plate from warping the plate.

Abstract: A block assembly for a lehr includes a plurality of blocks extending longitudinally, each of the blocks having a seal surface for mating and overlapping with an adjacent one of the blocks.

Abstract: The method of the present invention overcomes the hot-sticking problems between an inorganic non-metallic material (=insulator) to be molded and a forming die by maintaining an assembly comprising a forming die and the insulator in a polarized state during molding. Processes using said method lead to an improved surface quality of the molded insulator. A device for reducing said hot-sticking comprises a die (2) which acts as conductor, an electrode (3) which may act as support for the insulator (1) to be molded, means (5) for polarizing the assembly of said conductor, insulator and electrode which means (5) are connected by live electric wires (4) with said die and electrode.

Abstract: A glass slumping process includes the steps of supporting a thin sheet of glass upon a convex mold at a single, minimum area of contact of the glass sheet with the mold, the single area of contact being disposed inwardly of a perimeter of the glass sheet, heating the glass sheet to soften the glass sheet, slumping the glass sheet downwardly over a convex outer surface of the mold in response to the heating, while the glass sheet remains supported by the mold at the single area of contact, cooling the glass sheet and removing the glass sheet from the mold for use as a lamp shade.

Abstract: Ceramic decoration coloring substances substantially containing a zirconium pigment of the host lattice or inclusion type and a glass flux at a pigment volume concentration (PVC) of at least 30% have an increased color saturation C* if the glass flux comprises at least 71 wt. % PbO. Preferred decoration coloring substances have a PVC in the range from 40 to 70% and a PbO content of 75 to 85 wt. %. The decoration coloring substances are especially suitable for production of decorations, burned at 1000 to 1250°C, with increased color saturation C*.

Abstract: A method for manufacturing a glass container and an apparatus therefor capable of providing the container by pressing of a glass substrate using a die while keeping the glass substrate uniformly heated and softened. The glass substrate is heated while being kept lifted from a lower mold of a forming die and then subject to integral forming by the forming die. This permits the glass substrate to be integrally formed into the glass container in the form of a finished product, resulting in the number of steps and time required for processing being reduced.

Abstract: A method for lubricating glass contacting surfaces of glass forming equipment is disclosed. The method comprises the steps of delivering MAPD gas to a venturi at a low pressure, preferably below 10 p.s.i., and delivering oxygen to the venturi at a lower pressure, usually half or less than half of the pressure at which the MAPD gas is delivered to the venturi. The MAPD gas and the oxygen are mixed in the venturi and delivered to and through a nozzle which is directed toward a glass contacting surface. The mixture is ignited as it leaves the nozzle; its flow is controlled so that the temperature of the flame is between approximately 1500 and 1800 degrees K. By controlling the temperature of the flame, the method is operable to deposit on the glass contacting surface a lubricating coating of graphite including a substantial percentage of flat plate graphite.

Abstract: A system for tempering glass plates has preheating zone (1) in which several glass plates (7) stacked vertically in compartmented car (6) are heated together to a temperature below the tempering temperature of for example 650.degree. C. (for example 300.degree. C.). Preheated glass plates (7) are moved individually from preheating zone (1) into heating zone (2). In heating zone (2) glass plates (7) are heated to the tempering temperature, their being inclined to the vertical at an acute angle and being held by air cushions between two heating plates. On the lower edge of the two heating plates of heating zone (2) there is transport device which supports glass plates (7) simultaneously to the bottom. Glass plates (7) heated to the tempering temperature are moved into cooling zone (3) which has cooling plates aligned parallel to the heating plates and between which glass plate (7) is pushed for quenching.

Abstract: Glass sheets are bent in stages into the final shape in a horizontal position in two successive bending stations. The glass sheets heated to bending temperature are laid on a fabric carrier arranged resiliently on a rigid support frame. The glass sheets are conveyed stepwise with the fabric carrier and the support frame through the bending system, and are bent together with the fabric carrier which adapts to the shape of the glass sheets.

Abstract: Apparatus which is disclosed comprises a metal mold, a metal plunger and an annular manifold, and includes means for moving the plunger and the manifold between an open position in which the manifold surrounds the plunger and a gob of softened glass can be introduced into the mold and a closed position in which the manifold surrounds the plunger and the latter forms, with the mold and the manifold, a cavity in which a glass part can be formed. The manifold and the plunger have facing walls which are above the mold cavity, have portions which are in close fitting sliding engagement, and, thereabove, portions which diverge away from one another and form an annular space.

Abstract: A mesh belt is stretched in an annealing lehr and a plurality of fine mesh elements, which constitute a fine mesh having gas-permeability and elasticity, formed by weaving a heat-resistant wire, are fixed onto the mesh belt so as to be arranged along the moving direction of the mesh belt with predetermined spaces in the direction of the width of the mesh belt whereby a flaw which may be produced in a glass product to be annealed when it is placed on the mesh belt in the annealing lehr, is prevented.

Abstract: A glass forming lubricant comprising an organic titanate or an organic phospherous ester calcium salt as a lubricant agent.

Abstract: In a method of forming a mold release film on the surface of a glass blank from which an optical element is made by press molding, a carbon film having a thickness of less than 50 angstroms or, preferably, less than 10 angstroms is formed on the surface of the glass blank, thereby improving the releasability of the mold and the molded article with respect to each other. A glass blank (1) is subjected to ashing with an oxygen plasma so as to remove organic dirt attached to the glass blank (1). Then, plasma cleaning with an argon plasma is effected so as to remove inorganic dirt attached to the glass blank (1). Thereafter, the glass blank (1) is subjected to methane plasma processing such that a carbon film (2) having a thickness of less than 50 angstroms is formed on the surface of the glass blank (1) from which the dirt has been removed.

Abstract: An optical lens element is produced by the following steps of:preparing a glass pre-form;forming a metal thin layer or a powder layer, said metal thin layer including gold, platinum, rhodium, nickel, or palladium; andpressing the glass pre-form with the metal thin layer against molding surfaces to form the optical lens element.

Abstract: The present invention discloses a method of reducing marking of a heat softened glass sheet which results when portions of the sheet are contacted by glass sheet handling equipment. The portions of the sheet susceptible to marking are sprayed with an inert material having a melting point and decomposition temperature of at least 1200.degree. F. to form a layer that protects the sheet portion against marking from the equipment. In one particular embodiment of the invention, the lower major surface of a glass sheet is sprayed with an aqueous solution of sodium sulfate to form a layer of sodium sulfate along the glass surface which protect against marking of the glass by conveyor rolls.

Abstract: A process for the treatment of a glass to reduce or remove its wettability by gallium is provided, wherein the glass is treated with a silyling agent. Also is provided an apparatus comprising at least one hollow element containing a gallium or gallium based alloy or in which a gallium or gallium based alloy can circulate, wherein the glass forming the hollow element has been treated using the process. The apparatus may be thermometer, barometer or electric switch.