when was glass first used for window panes?

Answer 1

In the middle ages (medievel times).
The first windowpanes were small squares of glass that were held together with lead strips. (Leaded glass)
Sheet glass was first made in the 11th. century,
See the following article:

About 1000 AD, an important technical breakthrough was made in Northern Europe when soda glass was replaced by glass made from a much more readily available material: potash obtained from wood ashes. From this point on, northern glass differed significantly from that made in the Mediterranean area, where soda remained in common use. The 11th century saw the emergence, in Germany, of new ways of making sheet glass by blowing spheres, swinging these out to form cylinders, cutting these while still hot, and then flattening the sheets. This technique was perfected in 13th century Venice. Until the 12th century, stained glass (i.e., glass with some coloring impurities, usually metals) was not widely used. The centre for glass making from the 14th century was Venice, which developed many new techniques and became the center of a lucrative export trade in dinner ware, mirrors, and other luxury items. Eventually some of the Venetian glass workers moved to other areas of northern Europe and glass making spread with them. The Crown glass process was used up to the mid-1800s. In this process, the glassblower would spin around 9 lb (4 kg) of molten glass at the end of a rod until it flattened into a disk approximately 5 ft (1.5 m) in diameter. The disk would then be cut into panes. Venetian glass was highly prized between the 10th and 14th centuries as they managed to keep the process secret. Around 1688, a process for casting glass was developed, which led to its becoming a much more commonly used material. The invention of the glass pressing machine in 1827 allowed the mass production of inexpensive glass articles. The Cylinder method was invented by William J. Blenko in the early 1900s. Art is sometimes etched into glass via acid or other caustic substance (causing the image to be eaten into the glass). Traditionally this was done by a trained artisan after the glass was blown or cast. In the 1920s a new mold-etch process was invented, in which art was etched directly into the mold, so that each cast piece emerged from the mold with the image already on the surface of the glass. This reduced manufacturing costs and, combined with a wider use of colored glass, led to cheap popular glassware in the 1930s, which later became known as Depression glass.

Answer 2

http://www.uh.edu/engines/epi1282.htm
(discussion of first window glass)


GLASS MANUFACTURE IN THE UNITED KINGDOM - CHRONOLOGY

Window Glass was not produced in significant quantities in this country until :-

1226 BROAD SHEET was first made in Sussex, but of poor quality, and fairly opaque. Manufacture slowly decreased and ceased by the early 16th Century.
1330 French glassmakers produced CROWN GLASS for the first time at Rouen. Some French Crown and Broad Sheet was imported into the UK.
1620 BLOWN PLATE was produced in London by grinding and polishing Broad Sheet, and was used for mirrors and Coach Plates.
1678 CROWN GLASS was first produced in London. Because of its finer quality, this process predominated until the mid nineteenth century.
1688 The French produced POLISHED PLATE in larger sizes by casting and hand polishing.
1773 English POLISHED PLATE by the French process was produced at Ravenshead. By 1800 a steam engine was used to carry out the grinding and polishing of the cast glass.
1834 Robert Lucas Chance introduced IMPROVED CYLINDER SHEET, using a German process to produce finer quality and larger panes. This glass was used to glaze The Crystal Palace. The process was used extensively until early in the 20th Century to make window glass. From this period onwards machines were developed to automate the production of obscured Glass and later, window glass.
1847 James Hartley introduced a ROLLED PLATE glass with obscured ribbed finish, which is often found glazed in the roofs of railway termini.
1888 Chance Bros introduced MACHINE ROLLED patterned glass.
1898 Pilkingtons introduced Hexagonal Rolled WIRED CAST.
1903 MACHINE DRAWN CYLINDER Glass invented in the USA, was manufactured in the UK by Pilkingtons from 1910 to 1933.
1913 Belgium produced the first machine FLAT DRAWN SHEET glass. It was first drawn in the UK in 1919 in Kent .
1923 First UK production of continuous POLISHED PLATE glass, using single grinding system.
1938 Pilkingtons developed the twin ground POLISHED PLATE system.
1959 FLOAT GLASS was launched on the UK Market, invented by Sir Alistair Pilkington.

Answer 3

When wood became opaque. Mental head.

Answer 4

http://www.londoncrownglass.co.uk/History.html


http://www.great-glass.co.uk/glass%20notes/history.htm

Very interesting.

Enjoy.