Advances in the field of flat glass in the last thirty years

Mario Moretti


Starting in 1970, the evolution of flat glass has rapidly advanced.
Some examples can give us an idea of the advances made in the glass industry in various applications:

- Thermal and acoustic insulation of sheets have increased considerably.
Shortly, there will be a technological revolution in the construction field: insulating windows will be produced with a very low thermal transmission coefficient.
They will be 'vacuum' insulating windows, 8mm thick (currently, to obtain the same insulation, the thickness of the double windows is 24 mm).
The glass walls will have a level of insulation higher than that of stone walls!

- For very big surfaces, we have reached a fire resistance of 45 minutes, when 20-30 years ago, the glass did not even exist.

- In the area of protection, special glass has been created which is resistant to explosives and gun-shots, when, beforehand, it was enough to throw a stone to break a window.

In the building industry, glass has now become a structural element.

One example of this is the Piramide del Louvre, whose construction required the use of 675 rhombuses of glass, 2.90 x 1.90 metres big, weighing 140 kg each, and 118 triangles with a 1.90 metre base and a height of 1.50 metres. They are made of extra white laminated glass 10 millimetres thick.
Glass beams are being used to hold up glass ceilings; glass is even used to make footbridges (Il nuovo ponte - The new bridge - is under construction over the Grand Canal in Venice).
In parallel to the evolution of glass as a structural element, laminated glass products with varying photometric properties are being used more:
These is the so-called intelligent glass:
- Liquid crystal glass: laminated glass consisting of two sheets and two insertion layers between which an 'LC' liquid crystal film is placed. At rest, the crystals have any kind of direction and the glass looks translucent; under the influence of an electric field, the crystals assume the same direction and the glass becomes transparent.
These products have been on the market for some years.
- Photochromic glass, whose transparency varies depending on the quantity of light. Large surface windows are already is use in this regard.
- Thermochromic glass, which changes colour depending on the temperature. Small-sized ones have been produced in research centres.
- Electrochromic windows which change colour when subjected to an electrical field. These are already on the market.