Explain that different types of light are part of the electromagnetic spectrum. UV light has a wavelength slightly shorter than visible light. Unlike visible light, we can’t see UV, but some materials react in its presence. An ingredient in tonic water, called quinine, absorbs UV and releases it, causing it to glow blue (or fluoresce). depending on the plastic, the general mechanism involves the material absorbing the UV energy and producing a free radical. Free radicals then propagate within the material and change the physical and mechanical properties of the plastic[8]. The resistance of PTFE to UV light can be partly attributed to the strength of the carbon-fluorine general purpose acrylic naturally filters all UV light below 345nm (100% UVB), but only 35% of UVA light. OP-3 is a grade of acrylic that filters 98% of UVA as well. It is also possible to get PC with UV-blocking coatings applied. It’s also possible to get PET film dyed to absorb UVA, UVB, and UVC: edmundoptics.com Smaller the aggregate than 20 microns, greater is the surface area and in turn greater the UV absorption. Because carbon black absorbs and scatters UV light in the same way as visible light, the Fluorescence is the emission of light by a substance that has absorbed light or other electromagnetic radiation. It is a form of luminescence. In most cases, the emitted light has a longer wavelength, and therefore a lower photon energy, than the absorbed radiation. That’s the glow you see. Some toothpastes have fluorescent whiteners. They’ll make your smile so bright it glows in the dark. Humans see fluorescence best in the dark because we can’t see ultraviolet light. It’s outside the range of rainbow colors that our eyes respond to. When invisible UV light makes something fluoresce in the dark Titanium dioxide (TiO 2) is one of the most important pigments. It is widely used because it efficiently scatters visible and absorbs UV light, thereby imparting whiteness, brightness, and opacity when incorporated into a plastic. TiO 2 is commercially available in two crystal structures—anatase and rutile. Rutile TiO 2 pigments are preferred Clothing manufacturers may add chemicals that absorb UV light to clothing during the manufacturing process. Laundry additives, such as optical brightening agents and UV-disrupting compounds, can Stilbenes were first synthesized in 1843, 35 but it was not until 1945 that their Z/E photoisomerization was discovered (Figure 4 A). 31 Traditional non-functionalized stilbene derivatives strictly absorb UV light, with peak absorption at 294 nm for E-stilbene and 278 nm for Z-stilbene. 36 Notably, absorption of UV light by the Z isomer not In summary, the conversation discusses the concept of transparency and the role of glass in allowing certain wavelengths of light to pass through. It is explained that glass is transparent to visible light, but absorbs UV light due to the energy levels of the electrons in the material. However, it is also noted that glass is opaque to lower I5Gn.