Manufacture of glass(composition)

MANUFACTURE OF GLASS

SYNOPSIS

• INTRODUCTION

•TYPES

•METHODS

THE GLASS WAS DISCOVERED IN THE REGION OF SYRIA AROUND 5000BC

INTRODUCTION

INTRODUCTION

•The glass was first discovered in the region of

syria around 5000 BC

•It is an amorphous compound

•It is also known as super cooled liquid

•It has no melting point

•It has high viscosity which prevents from

crystallizing

TYPES OF GLASS MATERIAL

Variety of ophthalmic glass material

Crown glass >>>>> RI= 1.523

Barium crown glass >>>>> RI= 1.6

Borosilicate crown glass >>>>> RI= 1.53

Flint glass >>>>> RI= 1.75

COMPOSITION OF CROWN GLASS

70% of silica [si]

12% of calcium oxide (or) lime [cao]

15% of sodium oxide [Nao]

Small percentages of following compound acts as refining materials which improves the quality of glass

Potassium [Ka]

Borax [Na2B4O7.10H2O]

Antimony [sb]

Arsenic [As]

CROWN GLASS

COMPOSITION OF BARIUM

CROWN GLASS

35% of barium oxide[Bao]

30%of silica[Si]

Small percentage of following materials

Lime[Cao]

Zinc[Zn]

Alumina[Al]

Borax[Na2B4O7.10H2O]

NOTE:the effect of barium oxide is to increase the refractive index

BARIUM CROWN GLASS

BOROSILICATE CROWN GLASS

• Borosilicate crown glass is used for

windows,lenses and prisms

• Transmission ranges between 0.4µm to 1.4µm

BOROSILICATE CROWN GLASS

COMPOSITION OF FLINT GLASS

60% of lead oxide

30% of silica

8% of soda and potash

Small percentage of arsenic and antimony

NOTE:the effect of lead oxide is to increase the refractive index

FLINT GLASS

METHODS

There are two methods of manufacturing of glass

Individual batch method

Continuous flow method

• Six stages are common in both method

Mixing

Melting

Fining

Stirring

Forming

Annealing

THANK YOU

REFERENCE:

http://www.historyofglass.com/

http://www.pfg.co.za/all-about-glass.aspx

http://www.slideshare.net/Alizeeshansuhail/spectacle-lens-materials

http://www.janostech.com/knowledge-center/optical-materials-guide/borosilicate-crown-glass-bk-7.html

The principles of ophthalmic lenses- M.jalie