Science · 6 pages · 12 min
Why ultraviolet light can fade a dye
Ultraviolet photons carry enough energy to break the bonds that give a dye its color.
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From the opening
Ultraviolet light fades a dye because those photons carry enough energy to break or rearrange bonds in the color molecule. Once the structure that set the color is gone, the molecule no longer absorbs the same visible light, and the cloth looks pale. The opening covers photons energetic enough to break bonds, why the shaded side stays rich, and visible light is a weaker editor.
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Inside
- Photons energetic enough to break bonds
- Why the shaded side stays rich
- Visible light is a weaker editor
- Oxygen often joins the reaction
- Where the idea stops applying
- A distinction worth keeping
Sources
- Photochemical damage by ultraviolet photons
- Absorption by dye molecules that sets visible color