The history of glass

Glass in history: the origins

"From its beginnings right up to the present day. According to a tale by Pliny, glass was an accidental discovery attributed to some Phoenician merchants who, around 5000 BCE, disembarked near the banks of the River Belo in Syria, lit a campfire and used some blocks of nitrate taken from the goods they were transporting underneath their saucepans.

""...""The natron, melting from the heat of the fire, and mixing with the sand from the beach, produced a new transparent liquid produced from this mixture…"".

This is probably a myth with its roots in the fact that many glassworks in antiquity and still at the time of Pliny used to stock up on sand from the banks of the Belo. The Romans contributed significantly to the development of the glass industry.

Around 100 BCE, they developed production by blowing into moulds, thereby increasing greatly the potential range of items. They were the first to invent and use glass in windows. Cicero writes: ""… Those who do not have a house carpeted with glass plaques are to be considered practically paupers"".

Such was the development of the glass industry that in 200 ACE, the Emperor Severius imposed a tax on glass products against the background of a vast operation of bringing morality to their customs.

But the history of glass is filled by more tax exemptions than tax paid; in the following century, Constantine and Constant exempted glass workers from all duty or unfair taxes. In 500-600 ACE a new process was invented for making flat glass, by blowing a sphere and then successively enlarging it by turning it in a furnace. Up to the 19th century, the majority of flat glass was produced using this system.

The central point was known as the 'bull’s eye’ and, set in lead, was used for the typical stained-glass windows. There is still the memory of glass printed 'on rollers'.



Glass in history: Venice and Murano

Several historians tell of Crusaders bringing the art of glass working from the East to Venice, where it became established during the 11th century. Since the presence of furnaces was often the cause of fires, the Great Council decree of 1291 moved them all to the small island of Murano.

Concentrating everyone here also had the aim of facilitating the work of strict surveillance to ensure that the secrets of the art of glassmaking would not be exported .A worker who went abroad was liable to heavy penalties, being ordered to return, the arrest of family members, and…"" if, despite the imprisonment of his family, he persisted in wishing to live abroad, then some fine man will be employed to kill him…"".

And this is how an industry developed that for centuries made Murano synonymous with the art of glass working and today, the island is still one of the greatest centres for art like this. On Murano, the composition of a glass which, because of its extraordinary clarity was called 'CRYSTAL', was developed.


Glass in history: Saint Gobain

In 1665, Colbert awards the ""Manufacture Royale des Glaces"" the rights for the manufacture of cast glass.

And that's how SAINT GOBAIN started. After an unhappy initial experience when it tried to hire Venetian glass workers who stood out more for their quarrelsome natures and greed than for professional skill, the new company began the journey, which has taken it to becoming the leading European producer of flat glass.

The protectionist measures in the sector were on the other hand, extremely strong. In addition to the customs duty on Crystal imported to Venice, there was for the workers: the right to French citizenship after 8 years of residence; the right not to respond to the usual channels of justice but to the King’s Council; the right to gather raw materials; the right to exemption from all taxes. In 1700, SAINT-GOBAIN develops the system to produce large sheets of glass poured over tables, spread out with an enormous 'rolling pin' and then polished on its surface.

Cast crystal is created which, with subsequent improvements, will be the product which for three centuries will typify SAINT GOBAIN. 1959 sees the first experiments on FLOAT-GLASS (PILKINGTON). Subsequently, in 1964, in the Saint-Gobain premises in Pisa, construction of the first Float Glass plant in continental Europe begins; production starts in 1965. And that's how glass became part of life, history, even fairytales.

From Cinderella’s slippers to Snow White’s coffin; one of the most famous representations of glass slippers was made in the 16th century for Anne of Poitiers.


Glass in history: technical aspects

Moving away from the method of production, glass is a solid solution resulting from progressive solidifying, with no trace of crystallisation, of homogenous mixtures in fusion, mainly formed from silica, soda and lime.

To make glass, three basic elements must be melted together: A VITRESCENT, silica, introduced in the form of sand; A MELTING AGENT, soda or potash, in the form of sulphate or carbonate (lowers the silica’s fusion temperature); A STABILISER, lime, in the form of carbonate (gives the glass better resistance to water attacks).These three components have in fact been part of glass composition from time immemorial.

Today, the most up-to-date glass, produced in thousands of tonnes a day, is FLOAT GLASS. Glass obtained in this way, thanks to its extreme versatility and ability to be cut, milled, shaped while hot and tempered, is today being used increasingly extensively in the construction industry, in industry and in society at large. Its structure comprises practically all the elements of the periodic table, either directly or in the shape of oxides, with their related characteristics present to different degrees.

The introduction of certain metal composites, dissolved or dispersed in the mass in its colloidal state, gives the glass the ability to selectively absorb light radiation and therefore, colour. So, depending on the different metal composites used, different coloured glass will be produced (green, grey, bronze, blue, etc).

In construction, glass, due to its specific characteristics of transparency and surface hardness, represents the best solution to the requirement of contact with the outside and, at the same time, protection from it, typical of modern man. Used increasingly in buildings, it contributes often playing a major role in determining mechanical, acoustic and thermal characteristics.

For centuries, items made with glass have been conditioned by projection technology. Until 1800, architecture was a reworking of the styles of the past. It is only from the beginning of the 20th century that history has seen glass take its place as a lead player in architectural evolution. At this point, the coupling of glass with steel occurs and great precursors make use of this to create truly revolutionary works. The concept changes radically; from a filling material glass becomes a primary construction component.

Work both past and present bear witness to its aesthetic and practical worth. The glass industry has begun to use designers, producing items responsive to modern day requirements. We now see sheets of glass with a high technological content which help to make our house more comfortable.

Therefore, we have heat-insulated panels, filtering and reflective coloured crystal, tempered crystal for safety, shaped glass etc.

Of course, glass is used widely in other sectors, such as furnishing, lighting and decorative items.
In point of fact, these days actual furniture made of glass is being produced, and increasingly used in interior design, enabling designers worldwide to bring their projects to life.