The History of Glass

Abstract

Glass production is 5000 years old. Until the 1st century BC when blowing appeared in the Middle East, glass objects were mainly ornaments and small containers for cosmetics. Tiberius created a glass industry in Rome to satisfy the local customers more easily. Very soon, the western European glassmakers learnt to make glass themselves instead of importing ingots and processing them in secondary workshops. The collapse of the Roman Empire did not mean the disappearance of a product that has proved so useful. The art of glass was renewed during the Middle Age: stained glass windows appeared in numerous churches and cathedrals that were built all over Europe. The crusades enhanced the movement with new techniques coming from the East.

Glass was still made with sand and a flux but the flux changed from sodium to potassium salts produced by combustion of land plants instead of the Mediterranean coastal plants containing mainly sodium.

This composition was still used with a few improvements like purification of the ashes when industrial soda ash was invented at the beginning of the 19th century. The same century saw very important progress in glassmaking and it led to a huge decrease in price to the point where everyone could buy glass panes for their windows at the end of this period. Melting processes were also much improved. Use of coal was common since the 18th century, but the furnaces themselves had not really changed until the Siemens brothers invented the regenerative gas furnace where gas was produced with a gas producer. Ten years later, the tank furnace, a close ancestor of present-day melting furnaces, was introduced.

The forming processes had been improved since antiquity but the major changes occurred at the end of the 19th century when the processes were mechanized. As a result, the output increased spectacularly even after the end of the First World War, which took the lives of many glassworkers. Throughout the 20th century, the trend towards automation accelerated and melting tanks were applied to all types of glass. The middle of the century saw the revolutionary invention of float glass which laid the foundations for the modern glass industry.