Glass is everywhere! Its diversity of application is intimately linked to the very numerous properties of glass.
Glass has considerably changed our daily lives (eyewear, tableware, bottles and other containers), revolutionized architecture and become an integral part of less conspicuous and hyper-technical fields such as electricity, telecommunications, textiles and laboratory chemistry. This diversity of application is intimately linked to the very numerous properties of glass. transparency, capacity to take colour, plasticity and hardness make it a multipurpose material. The mystique surrounding the elusive nature of glass means that it has often been associated with myths, beliefs, special properties and even magical powers. Glass really is a material at the boundary of the physical and the metaphysical.
OPEN / CLOSED
A container has three main functions related to consuming, preserving and dispatching. For a long time the question of sealing was a difficult issue to resolve. Twists of straw, wooden pegs caulked with oakum and tallow, pieces of fabric (sometimes steeped in wax to prolong preservation) and plugs soaked in oil have all been tried and none prevented the contents from oxidizing and going bad. As for the ground glass stopper, a system made entirely of glass which obtained a seal through abrasion between the neck and the stopper, it did indeed ensure a hermetic seal to the satisfaction of chemists and pharmacists, but also risked breaking the neck when removing the stopper. First used in antiquity, the cork was rediscovered in the early 1600s and, with the invention of the corkscrew, came into general use in the following century. It has remained a ubiquitous solution ever since. Today, screw tops, flip tops, crown caps and other types of clip provide a wide range of closures that belie the technical prowess behind their invention.
Whether transparent or opaque, clear or coloured, when light comes into contact with glass, it is inevitably transformed. Because of the disordered state of the matter within the glass (an ‘amorphous solid’), light does not vary in speed as it passes through, thus making glass transparent. Adding metal oxides to glass gives colour which can be exploited to create beautiful works of art and everyday objects, and to enhance the (perceived) quality of the contents. Shopkeepers saw in it an opportunity to display dispensary bottles and sweet jars of great size and in eye-catching colours.
Glass is coloured for practical reasons, too, especially in the packaging of food and cosmetics. Adding metal oxides to the composition of glass enables it to filter some or all of the visible light rays, even UV light and for more technical applications, X-rays and gamma rays. If kept for several months, creams and perfumes will alter through contact with light. Opaque, dark blue or brown glass is used to prevent or delay this process, thus guaranteeing improved storage times.
LIFE / DEATH
In the middle of the nineteenth century the glass feeding bottle became a symbol of the efforts to reduce infant mortality. For far too long mothers and their babies struggled to survive the appalling hygienic conditions in France, with a maternal death rate close to 6% and infant mortality at 22%, which soared to 90% for children abandoned during the Second Empire (1851–1870)! Various factors were identified, including the lack of sterilized milk, poor quality milk and unhygienic feeding bottles. Only the implementation of a hygiene campaign would succeed in turning around the dismal trend at the dawn of the First World War. In 2011 the European Union banned the sale of feeding bottles containing bisphenol A, an endocrine disruptor present in certain plastics. This led to a resurgence in the demand for glass feeding bottles.
At life’s end, glass objects have been buried alongside the dead since antiquity. At life’s end, glass objects have been buried alongside the dead since antiquity. Bodies were burned on a bonfire alongside their personal effects and phials of perfumed oil called balsamariums. The ash was then preserved in a ceramic or glass urn.