3. THE GLASS WAS DISCOVERED IN THE
REGION OF SYRIA AROUND 5000BC
INTRODUCTION
INTRODUCTION
4. •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
9. 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]
12. 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
18. 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