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Glass Technology

Glass Technology

Date posted: June 13, 2017 // Glass

This remarkable material, created by the action of intense heat on silicon dioxide, was probably first recognised as the hard residue formed by lightning strikes on sand. For centuries, the man-made version has provided human beings with the vessels in which to store liquids, as well as those from which to drink water, wine and other beverages. In addition, it has provided us with transparent windows with which to protect ourselves and the contents of our homes from the effects of wind, rain, and the extremes of heat and cold, yet permitting us a view of the world beyond our walls.

Coloured forms of this same material have also provided the artist with an ideal medium with which to fashion decorative ornaments and artefacts, with the power to stimulate the senses and to enhance the living space. A number of significant advances in glass technology achieved in more recent times, however, have led to modified properties that have enabled the use of this exceptionally versatile material in a number of new and interesting ways.

In most cases, the modified properties in question have been achieved by the addition of various chemicals to the basic silica substrate. Notable exceptions, however, are the laminated composites that have allowed the development of safety windscreens to protect drivers and their passengers from deadly flying shards in the event of an impact.

One of the most significant modifications, and a major milestone in the glass technology of the time, is attributed to an Englishman named George Ravenscroft. Although his reasons are still uncertain, in 1673, he substituted lead oxide for the calcium oxide normally used, in order to lower the melting point of the mix. The result was a softer material, which was easier to work with, and possessed a higher refractive index that added to its brilliance – thus lead crystal was born. For this purpose, a lead content of 30% proved to be ideal. However, no one could have anticipated that, centuries later, when the dangers of repeated exposure to X-rays became apparent, increasing its lead content to around 70% would provide a window material that allows radiographers and radiotherapists to observe their patients, and technicians to handle radioactive isotopes, while remaining safe from the effects of ionising radiation.

On the domestic scene also, further developments in modern glass technology have led to a number of innovative applications. For example, the wire guards that were once placed in front of an open fireplace to protect people and property from flying sparks, have now been replaced by heat-resistant windows that conduct the warmth, and allow an unobstructed view of the glowing coals and flames, yet are able to resist thermal damage. A similar material has also become a common sight in the modern kitchen, where it is used to conceal the radiant rings of electric hobs, thereby providing their owners with a smooth surface that is easy to clean.

In the workplace, advances have led to transparent doors and windows that provide a fire-proof barrier to protect employees and facilitate their escape in the event of a fire. Other variants provide UV protection or additional strength for use in structures, such as staircases.

Acknowledged specialists in modern glass technology, LIT Africa is a leading supplier to the South African market.