The molecule 7-dehydrocholesterol produces vitamin D 3 when skin is exposed to ultraviolet light in an environment in which the UV index is 3 or greater. Vitamin D 3 is a precursor to active vitamin D, which is essential in calcium metabolism. Production of vitamin D3 within the skin when 7-dehydrocholesterol is exposed to UV light. Lightweight. Durable. UV resistant. Heat resistant: it can withstand up to 248F of heat. 3. High-Density Polyethylene (HDPE) This type of plastic is ideal for outdoor use because of the following features; Incredibly enduring: can sustain a substantial amount of weight. Softer than acrylic and polycarbonate. Details. ACRYLITE® Gallery OP3 UV Acrylic (plexi-glass) is recommended for professional presentation and preservation framing of artwork, photography and other works on paper. Galleries and museums specify OP3 to filter 99% of harmful UV rays, while remaining color neutral. It is lightweight, acid-free, shatter-resistant and 3/32” in thickness. Polymethyl methacrylate or PMMA is more popularly known as acrylic. It is a transparent and rigid thermoplastic. It is produced from the monomer methyl methacrylate. PMMA shows high resistance to UV light and weathering. Due to its transparency, PMMA is used in car windows, smartphone screens to aquariums. It is a tough plastic, easy to shape Is it possible for UV light to pass through plexiglass? It may not be possible to totally avoid colour fading or discoloration due to UV plexiglass but it can block up to 98 percent of harmful UV light from reaching the surface. The UV protection provided by this acrylic sheeting is limited to wavelengths less than 400 nanometers in length. Plexiglass starts out clearer than glass but will yellow in sunlight. The transmissivity of plexiglass (up to 92%) is higher than that of glass (80 – 90%) so it looks clear even in thick sheets. For this reason, is often preferred for museum display applications. However, plexiglass can gradually turn yellow when exposed to UV (sunlight) light. Babblings. Now, the change in the texture of the plexiglass sheet could be due to a lot of reasons. While sunlight exposure is an important issue, it is not the only issue causing your glass sheet’s texture to destroy and the sheet to bubble up and crack. So, it is important to realize that an instant temperature change is also a vital factor A: While acrylic softens at higher temperatures, it does not actually melt until it reaches 320 °F (160 °C). Therefore, normal household use does not risk melting acrylic. Hot stovetop items should only be placed on an acrylic tabletop surface using a protective trivet or other padding, preferably with rubber cushions. jNYD4D.