In spite of its tendency to break when handled roughly, optical transparency and thermal properties make glass ideal for items ranging from drinking vessels and laboratory containers to works of art.
Chemistry has not only played a role in making glass, glass has played a prominent role in the progress of chemistry through glass flasks and beakers, glass wool to insulate reactions, and optics for instrumentation.
The primary component of glass is silica, SiO2, which may be used in a pure form to yield fused quartz, but extremely high glass transition temperature of this material makes it challenging to work with. Various additives such as sodium carbonate are added to the silica to reduce the glass transition temperature with additional ingredients of lime, aluminum oxide, and magnesium oxide used to make glass that is more chemically durable. This mixture, known as soda-lime glass, is the composition of 90% of manufactured glass.
Borosilicate glass, known as Pyrex, is a combination of silica and boron oxide. This material has a low thermal expansion coefficient which makes it less prone to cracking when exposed to extreme temperature changes, so it is useful for laboratory beakers and household cookware.
It is a common myth that glass continues to flow over time with evidence being cited that many older windows are thicker at the bottom than at the top. This variation actually arises from the historic process used to form plate glass which involved spinning the glass into a sheet. The material on the outer edge was thicker than the inner glass, which resulted in the slightly uneven distribution. When mounting the glass in a window frame, the thicker edge was placed at the bottom to ensure stability.
Certainly some of the most spectacular applications of glass are in the area of art and architecture. Louis Comfort Tiffany made his name as a master of stained glass whether in lamps or in windows, and he experimented with different methods of imparting glass with color and texture. Artists such as Dale Chihuly create magnificent sculptures similarly using glass to explore form and hue.
More information about the techniques and history of glassmaking may be found at http://www.sha.org/bottle/glassmaking.htm