Continued studies in the deterioration of glass
Conservation Journal
Autumn 2002 Issue 42
Research Associate, Department of Materials, Imperial College, London
It has been well documented over many years that certain types of glassware displayed within the glass collection at the V&A are susceptible to deterioration over time. Typically the group of artefacts particularly prone to this process is Venetian glassware of the 16th and 17th centuries. It has been suggested that the instability of glass from this period is due to the purification of the raw products, such as plant ashes, for obtaining ‘a more clear and crystal glass’ 1 . Refining the raw materials produced a clear glass that could be worked at lower temperatures, but the composition of the glass had been altered. The purification process led to a glass with a low calcium oxide (lime) content and a high sodium oxide (soda) or potassium oxide (potash) content.