It's not WINDOW GLASS, It's Tru Vue:

The Frame Shop Gallery chooses only Tru Vue for our customer's projects. As true conservation framers, we know the glass you choose makes a significant difference in your projects life expectancy.

Tru Vue sets the standard in quality picture frame glazing that enhances, protects, and beautifies.  From custom framing to conservation and preservation in museums and galleries across the globe, Tru Vue is known as a leader and innovator in the protection and conservation of all things framed and displayed. Tru Vue's advanced, optically coated glazing products help protect framed art from up to 99 percent of harmful indoor and outdoor UV rays—UV rays that can cause art to fade over time. And our magnetron sputtered, anti-reflective coating is engineered for demanding optical requirements, durability, and strength.  No matter what Tru Vue® glass or acrylic you use, you can be sure you’re showcasing and protecting works of art and displays with the highest quality glazing in the industry.

Museum Glass®
is the best glazing option for all framed works of art (it is used on the violin, right).  Museum Glass is the highest quality anti-reflective picture framing glass available in the industry.  Tru Vue® has a proprietary manufacturing process, called Magnetron Sputtering, which produces an ultra protective, nearly invisible finish.  It protects against 99% of harmful indoor and outdoor UV light rays and has the highest light transmission along with the lowest reflection rating of any other glass product.  The result is consistent, durable quality and the most attractive display for artwork.

Conservation Reflection Control®
with 99% UV Protection is chemically finished on one side, scattering light as it strikes the glass.  This matte-like finish enhances the beauty of the artwork by protecting the piece from unwanted glare or distortion.  Additionally, the UV protection helps protect fading, discoloration and embrittlement caused by harmful light rays. 

Conservation Clear®
Tru Vue uses a proprietary coating process of microscopic, silica-based UV blocking agents that are cured onto the surface of a glass substrate to produce an ultra protective lite of glass that enhances true colors and protects art from fading.  Over time, indoor and outdoor ultraviolet rays take a toll on artwork and cause fading.  Paper can become faded, discolored, and brittle, causing irreversible damage that ruins the artwork.  Conservation Clear framing glass with 99% UV protection helps protect art from fading by blocking harmful indoor and outdoor light rays, preserving art for years longer than regular glass.

Reflection Control®
Glass can act like a mirror, causing glare and distracting viewers from the works of art on display.  Reflection Control® glass is chemically finished to scatter light as it strikes the glass.  This subtle, matte-like treatment protects artwork from unwanted glare or distortion. 

Premium Clear®
Artwork deserves the highest quality regular glass available and you can find it with Tru Vue Premium Clear framing glass.  This quality durable glass showcases your artwork.

Optium Acrylic® is a lightweight, anti-reflective, anti-static, clear-coated acrylic that provides greater security than traditional glazing.