Archaeologists have found evidence of man-made glass which dates back to 4000 BC; this took the form of glazes used for coating stone beads. It was not, however, until 1500 BC that the first hollow glass container was made by covering a sand core with a layer of molten glass.
Glass blowing became the most common way to make glass containers from the First Century BC. However, the glass made during this time was highly coloured due to the impurities of the raw material. It was not until the First Century AD when colourless glass was produced and then coloured by the addition of colouring materials.
Although the origins of glass can be dated back as far as 4000 BC, the glass we have in our windows today, Flat Glass, is extremely recent.
Flat glass was pioneered in the 1950s by Pilkington. The process involves pouring molten glass onto molten metal (commonly tin).
Prior to the innovation of float glass, the process of creating flat sheets of glass involved the traditional practice of ‘blowing’ the glass into a cylinder, which was then cut and flattened. With this process there was a limit of the size of glass than could be made.
When Pilkington came up with the Float Glass process in the 50s this all changed. They made it possible for glass to be manufactured in all sizes and thicknesses.