GlassGroup 6

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How it started…Glass was first manufactured in open pits in ca. 3000 B.C. until the blowpipe was invented in ca. 50 B.C.

Nowadays, wealso use moldsand machines.

Characteristics of glass• It is brittle.• Discoloration signifies wear.• Can be formed either with molds or

blowing/manipulation.• It is non-conductive.• It can be either transparent, translucent or

opaque.• It’s chemical and physical properties remain

unchanged after heat-treatment.

Production• While pure silica can be made into glass for special

applications other substances are added to common glass to simplify processing (ex. Sodium Carbonate in soda-lime glass).

• As well as soda and lime, most common glass has other ingredients added to change its properties (ex. Lead, Boron, Iron & Barium).

• Besides the chemicals mentioned, in some furnaces recycled glass ("cullet") is added, originating from the same factory or other sources. Cullet leads to savings not only in the raw materials, but also in the energy consumption of the glass furnace.

Production• Following the glass batch preparation and mixing the raw

materials are transported to the furnace. • After melting, homogenization and refining (removal of

bubbles) the glass is formed (ex. Container glass for common bottles and jars is formed by blowing and pressing methods.).

• Once the desired form is obtained, glass is usually annealed for the removal of stresses.

• Various surface treatment techniques, coatings, or lamination may follow to improve the chemical durability, strength, or optical properties.

• Glass polymerization is a technique that can be used to incorporate additives that modify the properties of glass that would otherwise be destroyed during high temperature preparation.

Application• Ordinary glass is prevalent due to its transparency to

visible light.• Laboratory equipment are often made of borosilicate glass for

its low coefficient of thermal expansion, giving greater resistance to thermal shock and greater accuracy in measurements. For high-temperature applications, quartz glass is used, although it is very difficult to work.

• Glass is commonly used in buildings as transparent windows, internal glazed partitions, and as architectural features.

• It is also possible to use glass as a structural material, for example, in beams and columns, as well as in the form of "fins" for wind reinforcement, which are visible in many glass frontages like large shop windows.

Application• However, glass cannot carry heavy loads because it’s

brittle and has a tendency to shatter on impact.• Glass can also be used for insulation (ex. Fiberglass &

Foamed glass.)

• Some glass (ex. SiO2 glass) can absorb UV rays.

• Glass mirrors, lenses or prisms.• Glass can also be manipu-

lated into art-forms(ex. Glass blowing, glass molding, etc.).

Types of GlassSheet Glass Energy Efficient Glass

Self Cleaning Glass

Float Glass

Types of GlassPatterned Glass Toughened

Glass

Laminated GlassWired Glass

Types of GlassMirrors

Picture Frame Glass