Glass has widespread use and can be produced through different manufacturing processes. It is made by melting raw materials like silica sand, soda ash, and limestone at high temperatures. In the float glass process developed in the 1950s, molten glass flows on a bath of molten tin and is cut to size after annealing and inspection. Glass can be strengthened, tinted, low-emissivity coated, or made obscure/self-cleaning for various applications like windows, touchscreens, lenses, and decorative pieces. Standards like IS codes regulate glass production and properties in India.

1. Topic : Glass
PC-46 : Nishu Singh
PC-67 : Sannyam Gupta
PC-68 : Prajwal Wagh
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2. History :
Glass is a non-crystalline, often transparent amorphous solid, that has widespread practical,
technological, and decorative use in many fields.
Naturally occurring obsidian glass was used by Stone
age societies as it fractures along very sharp edges,
making it ideal for cutting tools and weapons.
Archaeological evidence suggests that the first true
synthetic glass was made in Lebanon and the coastal
north Syria, Mesopotamia, or ancient Egypt. The early
glass was rarely transparent and often contained
impurities and imperfections, and is technically
faience rather than true glass, which did not appear
until the 15th century BC.
Early glass was rarely transparent and often
contained impurities and imperfections and is
technically faience rather than true glass, which did
not appear until the 15th century BC. During the Late
Bronze age there was a rapid growth in glassmaking
technology in Egypt and Western Asia.
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3. In the 21st century, glass manufacturers have developed different brands of chemically
strengthened glass for widespread application in touchscreens for smartphones, tablet computers,
and many other types of information appliances.
In the 1950s, Pilkington Bros., England, developed the float glass process, producing high-quality
distortion free flat sheets of glass by floating on molten tin. The production of lenses has become
increasingly proficient, aiding astronomers as well as having other applications in medicine and
science.
During the 13th century, the island of Murano, Venice, became a center for glass making, building
on medieval techniques to produce colorful ornamental pieces in large quantities.
Towards the end of the 17th century, Bohemia became an important region for glass
production, remaining so until the start of the 20th century. Throughout the 20th century,
new mass production techniques led to the widespread availability and utility for bulk glass and its
increased use as a building material and new applications of glass.
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4. Glass Manufacturing Process :
Production of Glass
It consists of the following steps:
● Melting & Refining:
Fine grained ingredients closely controlled for quality, are mixed to make a batch, which flows into
the furnace, which is heated up to 1500 degree Celsius. This temperature is the melting point of
glass.
The raw materials that float glass is made up of are: Silica Sand, Sodium Oxide from Soda Ash,
Calcium oxide from Limestone, Dolomite & Feldspar.
The above raw materials primarily mixed in batch helps to make clear glass. If certain metal oxides
are mixed to this batch they impart colors to the glass giving it a body tint. 4

5. ● Float Bath:
Glass from the furnace gently flows over the refractory spout on to the mirror-like surface of
molten tin, starting at 1100 deg Celsius and leaving the float bath as solid ribbon at 600 deg
Celsius.
● Coating (for making reflective glasses):
Coatings that make profound changes in optical properties can be applied by advanced high
temperature technology to the cooling ribbon of glass. Chemical Vapour Deposition (CVD) is the
most significant advance in the float process since it was invented.
● Annealing:
Despite the tranquillity with which the glass is formed, considerable stresses are developed in the
ribbon as the glass cools. The glass is made to move through the annealing lehr where such
internal stresses are removed, as the glass is cooled gradually, to make the glass more prone to
cutting.
● Inspection:
To ensure the highest quality, glass manufacturers carry out inspection at every stage. Inspection
technology now allows 100 million inspections per second to be made across the ribbon, locating
flaws the unaided eye would be unable to see.
● Cutting to Order:
The entire process of glass making is finally complete when diamond steels trim off selvedge –
stressed edges- and cut ribbon to size dictated by the computer.
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6. Types of Glass :
● Laminated glass:
Laminated safety glass which made from at least 2 sheets of
tempered or heat strengthened glass which bonded together
across the entire surface by the special film widely used
interlayer is a PVB (Poly Vinyl Butyral).
● Tempered Glass :
Like tempered steel, the strength of glass can be increased by
rapid cooling in the manufacturing process, it will become 4
times stronger than normal glass. Often referred as safety
glass, it is highly resistant to breakage.
● Heat Strengthened :
Not as strong as tempered glass, heat strengthened glass is
manufactured using a lower temperature and whose strength
is 2 times greater than standard glass.
● Reflective Glass :
Reflective glass is glass that has been treated with a metallic
coating to allow it to reflect heat. This type of glass is used in
environmentally friendly construction with the goal of
reducing heat gain and loss, making structures much cheaper
to heat and cool over the course of the year.
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7. ● Tinted Glass :
Various colors can be added to the glass formula during
manufacturing. The tinting materials help filter sunlight as it
passes through. This reduces the amount of solar, or heat gain.
● Low-E-Glass :
A highly energy efficient glass that reflects heat producing long-
wave and ultraviolet light. It has been treated with an invisible
metal or metallic oxide coating, creating a surface that reflects
heat, while allowing light to pass through.
● Obscure Glass :
At least one side of the glass is finished in one of a various
number of textures that impede clarity.
● Self-Cleaning Glass :
A recent innovation is self-cleaning glass, aimed at building,
automotive and other technical applications. A nanometer-
scale coating of titanium dioxide on the outer surface of glass
introduces two mechanisms which lead to the self-cleaning
property.
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8. Practical Applications of Glass :
● Unlike any other material, glass can transmit, absorb or refract light. Such characteristics add
extraordinary beauty to your building.
● It is economic. Consider the fact that glass saves energy by allowing in natural light even when
you close your windows and doors. It also saves you on the electricity bill cost.
●It is weather resistant. Glass can withstand effects of rain, wind and the sun without losing its
integrity and appearance.
●Glass is also rust resistant. Unlike any other, it won’t degrade by chemical and the surrounding
environmental effects.
●You are much safer from electric hazards. The glass is a very excellent insulator. It is thus
impossible for it to conduct electric current.
●It is especially excellent for showrooms and showcases. Glass provides the means to showcase a
product.
●It has a smooth and glossy surface. As a result, glass is dust-proof and thus easy to clean.
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9. IS Codes :
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● IS 2553-1 (1990)
● IS 2835 (1987)
● IS 14900 (2000)
● IS 3548 (1988)

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