Short answers, pulled from the story.
Henry Seebohm observed the practical necessity for double glazing in 1877. He noted that winter temperatures in the Yeniseysk area of Siberia regularly fell below negative fifty degrees Celsius. Local builders had fitted a second pane of glass to improve insulation against the bitter cold.
Thomas Stetson patented an insulating glazing unit consisting of two glass panes bound together into a single unit with a seal between the edges in 1865. The technology evolved from older methods known as double-hung windows and storm windows. It was developed into a commercial product in the 1930s when several patents were filed.
The Libbey-Owens-Ford Glass Company announced their Thermopane brand name insulated glazing product in 1944. Their product was sold under the Thermopane brand name which had been registered as a trademark in 1941. This followed the development of the technology into a commercial product in the 1930s when several patents were filed.
Insulated glazing units typically last from 10 to 25 years depending on quality of materials used and size of gap between panes. Windows facing equator often last less than 12 years due to temperature differences and geographic location. IGUs typically carry warranty for 10 to 20 years depending upon manufacturer.
Sulfur hexafluoride is used particularly as sound proofing in Europe under F-Gas directive which controls usage. It has only two-thirds conductivity of argon but is stable and dense. Sulfur hexafluoride can replace or augment inert gas to improve acoustical attenuation performance.