industrial glass

Table of Contents

Introduction
Glass compositions and applications
- Oxide glasses
  - Silica-based
  - Nonsilica
- Nonoxide glasses
  - Heavy-metal fluoride glasses
  - Glassy metals
  - Semiconducting solids
- Glass ceramics
- Glass composites
- Natural glasses
Glass formation
- Volume and temperature changes
  - Cooling from the melt
  - The glass transformation range
  - Reheating
- Atomic structure
  - Sodium silicate glass
  - Nonsilicate glasses
- Glass-forming criteria
  - Zachariasen’s model
  - Kinetic arguments
- Phase separation
Properties of glass
- Physical properties
  - Density
  - Elasticity and plasticity
  - Strength and fracturing
- Thermal properties
  - Viscosity
  - Thermal expansion
  - Heat transfer
- Chemical properties
- Electrical properties
  - Electrical conductivity
  - Dielectric constant
  - Electronic conduction
- Optical properties
  - Transparency, opacity, and colour
  - Photosensitivity
  - Refraction and reflection of light
Glassmaking in the laboratory
Industrial glassmaking
- The raw materials
  - Chemical compounds
  - Cullet
- The glass-melting furnace
  - The melting chamber
  - The conditioning chamber
  - The forehearth
- Nonfusion glassmaking
  - From the solid state
  - From the gaseous state
  - From liquid solution
- Phase-separation techniques
  - The Vycor process
  - Glass ceramics
Glass forming
- Beads and microspheres
- Tableware
- Containers
- Lightbulbs
- Tubes and rods
- Flat glass
- Fibreglass
- Optical glass
- Optical fibres
  - Properties
  - Fabrication
- Glass seals
Glass treating
- Annealing
- Strengthening
  - Polishing and glazing
  - Thermal tempering
  - Ion exchange
  - Lamination
History of glassmaking
- Development of the glassmaker’s art
  - The ancient world
  - The Middle Ages and the Renaissance
  - Science in glassmaking
- Development of modern glassmaking
  - Glass melting
  - Container making
  - Flat glass
  - Optical glass

References & Edit History Related Topics

Images & Videos

Observe how a superhydrophobic multifunctional glass surface resists fogging, glare, and self cleans

Figure 2: The irregular arrangement of ions in a sodium silicate glass.

Figure 3: Basic building block of a silica glass network. Silicon ions bond to oxygen atoms, forming tetrahedral structures that are connected by a bridging oxygen atom. The tetrahedra revolve around the oxygen-silicon bond, while the angle at which the two tetrahedra are connected also varies.

Figure 4: Photomicrographs of phase separation in glass, showing (A) separation by the droplet mechanism and (B) separation by the spinodal mechanism.

Figure 5: The viscosity of representative silica glasses at varying temperatures.

$Figure 7: The refraction and reflection of light. (Left) When light strikes the boundary between glass and air at less than the critical angle (θc), it is refracted and partially reflected; (centre) when it meets the boundary at the critical angle, it is refracted parallel to the boundary; (right) when it meets the boundary at more than the critical angle, it is reflected totally.$

Figure 8: Schematic diagram of a glass-melting furnace, showing (A) a cross section and (B) a longitudinal section.

Figure 9: Newly formed bottles being transported by conveyor to the annealing lehr.

Figure 10: Schematic diagram of the float process for making flat glass. A glass ribbon, soft enough to be workable, is fed from a glass-melting furnace and passed between rollers into the float bath. There, it floats on molten tin under a controlled atmosphere of nitrogen and hydrogen (N2/H2) that prevents oxidation of the tin. As the bulk of that glass begins to cool, the surface is heated and polished in order to remove surface blemishes and then allowed to cool also. The ribbon exits the float bath and passes through the annealing lehr, where it is cooled uniformly in order to prevent the formation of nonuniform internal stresses that may warp the glass. The cooled glass is then scored by diamond-tipped cutters, and individual sheets are separated and stacked.

industrial glass: Related Content

Written and fact-checked by The Information Architects of Encyclopaedia Britannica

Photos and Videos

Figure 11: The forming of stepped-index optical fibre, using the double-crucible technique. Glass rods containing the core-glass and cladding-glass compositions of the eventual fibre are fed into two concentric platinum crucibles, which are heated in a silica-lined furnace. The two compositions melt under an inert atmosphere and flow through an orifice as a composite, concentric stream, the diameter of which is monitored by a fibre diameter scanner. After passing through primary and secondary polymer coatings and curing ovens (which cure the protective coatings through thermal or ultraviolet energy), the solidified optical fibre is wound around a capstan and onto a take-up reel.

$Figure 12: The preparation of graded-index optical fibre, using the modified chemical vapour deposition (MCVD) technique. A carrier gas of oxygen (O2) is bubbled through liquid silicon tetrachloride (SiCl4), phosphorus trichloride (PoCl3), and germanium tetrachloride (GeCl4). The resulting vapours are mixed in suitable proportions in a flow controller and then fed through a vapour inlet into a silica tube. Heat generated by a traversing oxygen and hydrogen (O2 and H2) torch sets off a vapour phase reaction in which a soot, containing silica as well as oxides of phosphorus and germanium, is deposited in a series of porous layers on the inside of the tube. The layers are dehydrated by gaseous sulfur oxychloride (SOCl2), and various exhaust products are vented through a vapour exhaust. The layers are then sintered, collapsed under vacuum, and condensed to concentric core and cladding layers of the desired refractive properties.$