A BRIEF HISTORY OF GLASS

According to the Roman historian, Pliny, a legend tells of Phoenician merchants returning from Egypt with with a cargo of sodium carbonate, who stopped to rest one night by a river. Since they had no stones on which to place their utensils while cooking, they used a few blocks of potassium nitrate instead, and a fire started that burnt all night.

The following morning, the merchants were surprised to see that instead of the river sand and sodium carbonate, they found a completely new, shiny and transparent material. Glass was formed by a combination of silica, a mineral found in river sand, with calcium carbonate which melted together thanks to the presence of soda ash, an alcaline substance.

The first vitreous compounds appeared about 3000 B.C. in Egypt and Mesopotamia, areas rich in quartz sand, the main component of glass.
The most ancient glass workmanship techniques allowed the production of small objects, mostly for ornamental use or rituals.
The first vases were produced about 1500 B.C., using the technique of glass melted around a sand core, with cold cutting and smoothing with a wheel.
Later on, in Syria, Egypt and Rome the simpler and more economic method of glass blowing was developed. Consequently, significant trade of glass objects began, used mainly for tableware and decorative purposes.
During the Middle Ages, to meet the architectural demands of large Gothic cathedrals with vast surfaces, glass window panels were produced with metallic framework and colored with a technique similar to enamel on glass.
Towards the end of the 15th century, Venice became the most prestigious glass producing center in the world.

During the second half of the 1700s, the economic and industrial revolution in England brought technical progress to glass manufacture, thus sparking a growing demand and a decrease in prices. Combinations of glass and iron were used in constructing large, luminous coverings. In the early 1800s, in France and England, large iron and glass skylights decorated numerous public buildings and exposition galleries: la Galerie d’Orléans at Palais Royal by Percier & Fontaine (1829), the Crystal Palace in London by Paxton (1851), Les Grandes Halles in Paris by V. Baltard (1853), la Galeries des Machines in Paris by Dutert & Contamin (1889).
At the beginning of the 1900s, in many European countries, an avant-garde movement was formed with a strong nationalistic tradition but differing in style, called art nouveau. During this period, glass acquired a more decorative function: colored glass embellished undulated façades and elegant coverings (some examples are Hotel Tassel –1893- Hotel Horta –1901- in Brussels by Victor Horta).
Expressionism brought a symbolic meaning to glass with a utopian outlook towards the future. The Glashaus (1914), a project by Bruno Taut for the Cologne Expo, demonstrated a more sacred attitude towards this material, a depository for expressionist utopias of a new society in formation. A collaboration between Taut and Paul Scheerbart gave rise to the Chain of Glass.

Glass combined with steel took on a new and important function in the 1920s, beginning with the international movement of Modernism. The main ideology perceived decorative art as a vehicle of semantic and functional meaning, not lacking morphological qualities. Modernism, which defines glass as light, space, optimism, became popular in Germany and France where Le Corbusier formed the “Union of Modern Artists” in 1930. This style later spread to the United States with the arrival of Ludwig Mies van der Rohe (1886-1969) from Germany and the construction of glass buildings with steel structures.
At the end of WWII, thanks to important technological progress in the glass industry and fundamental changes of attitude towards art and glass manufacture, a greater freedom of expression and experimentation evolved. The need for reconstruction in Europe during the post-war period, brought an increase in the use of glass for almost all of the building façades. Some examples are the Solow Building in New York, constructed by Skidmore, Owing & Merril in 1974 and the Tolmers Square Building in London, built by Renton, Howard Wood and the Levin Partnership nel 1982.
For architectural uses, the production of fireproof, ribbed or modelled glass in various forms and colored glass blocks that could be joined together like bricks began. Glass blocks became popular in the 60s and 70s for both interior and exterior walls. During the economic boom in the 50s and 60s, there were more funds for research so new materials were discovered and important innovations took place in mass production: some examples were the unintentional invention of glass-ceramic, improvements in lead crystal, the use of glass in illumination. During these years, groups of artists conducted studies on the degree of measurability and precision of the composite system; on movement with the aid of novelty materials and instruments (lasers and computers), on primary elements of form to the highest extreme of their dissolution into minimal art. More challenging projects brought continuous research on form, realized thanks to the discovery of new technology: the transparent sails supported by a tensioned structure that cover the Olympic Park in Munich, was constructed in 1968 from a project by Behnisch & Partner and F. Otto. Lightweight structures, expressions of ecology, ethics and technology were the major themes that Frei Otto addressed in his projects, through experimentation on materials and forms and extensive research on nature and biological elements.

During the last decades, glass has become very popular in the building sector. The main reasons have to do with developments in glass technology which has maintained the unique transparency of the material. In this manner, mechanical and workability characteristics have been improved, even though they represent a limitation for this material, allowing to optimize interior ambiences illuminated by continuous façades without framework, that open onto pleasant external spaces. Continuous façades are used mainly for work environments, for example the project by Samyn and Partners for the construction of the Solvay Research Centre in Brussels. Its main façade is closed by a transparent blade in glass panels without framework, sealed with silicone and fixed to the structure externally. This blade allows the creation of “panoramic studies” to stimulate meditation and communication. Continuous façades can also be used to create unusual optical effects. One example is the Dior Store in Tokyo, designed by Kazuko Sejima and Ryue Nishizawa in 2001. It is completely covered with flat panels of extra transparent glass, cut horizontally by the ceiling at various distances opposite translucent, curved acrylic screens that discretely allow haute couture fashion to filter through. One has the illusion of a higher number of floors and the sophisticated elegance of the renowned fashion house. The O Museum in Nagano, also designed by Kazuko Sejima and Ryue Nishizawa in 1999, is composed of a suspended volume behind a curtain wall, screen-printed with horizontal lines, gently curved to follow the passageway. A glass façade with a similar use is present in the addition to the Technical University of Brandenburg, at Cottbus designed in 1994 by Herzog & De Meuron. Here, curved glass panes acting as the outer shell are screenprinted with letters from different alphabets that create patterns reflecting the symbolic and calligraphic world. Last but not least, the glass pavillion at the Toledo Museum of Art in Ohio, designed by Kazuyo Sejima and Ryue Nishizawa in 2005, has curved glass walls anchored to a lightweight framework of steel columns and a thin, curved steel plate. When inside, the visitor has the impression he is walking among the trees surrounding the pavillion.
During the last few years, due to focus on energy conservation, we have witnessed a preference for ventilated façades: panels fastened to metallic framework or strategic supports that create a hanging detached from the supporting structure to improve insulation from the outside while forming an interspace for the hot air flow in a “chimney effect”, climatizing the building and reducing heating expenses.

Today, glass has obtained a high potential in architecture where it can be used not only as the “outer shell” of the structure, but also as a bona fide structural element.
The de-materialization of the structure has gone beyond proposals of closed glass systems to the realization of systems without framework, arriving directly at the core of the structure: nowadays glass beams and pillars represent the latest generation of transparent structures. The idea of creating structural elements like beams and pillars from a material that has always been considered fragile, may seem like a contradiction. However, paradoxes in construction must be taken seriously, and for this reason we must try and understand the innovations and numerous revolutionary aspects which this unique material can provide.