Can UV light penetrate through plastic or glass?

Can UV light penetrate through plastic or glass?

In principle, whether a light can pass through a material depends on whether the energy of this light can be absorbed by the material, each material has its own intrinsic frequency of electrons in the molecules, when the frequency of light and the intrinsic frequency of these electrons are the same, the light energy of this light will cross the energy gap to activate the low-energy state of the electrons to the high-energy state, thus converting the light energy into other forms of energy.

In addition the ability to resist light is also proportional to the concentration and thickness of the light-absorbing material, which can be referred to Beer's Law (Beer's Law).

Compared with visible light, ultraviolet energy is relatively large, so to allow the passage of ultraviolet light is not absorbed, the need for a relatively large energy gap of the material to do. Most of the glass and plastic do not meet this condition, so it is difficult to let ultraviolet light, especially the lower wavelength part of the penetration, generally speaking, the resistance rate is more than 90%.

Ultraviolet light is divided according to wavelength: near ultraviolet (UVA), far ultraviolet (UVB) and ultra-short ultraviolet (UVC). Although ultraviolet light has a penetrating effect on human skin, and the longer the wavelength of ultraviolet light, the greater the danger to human skin, but can not penetrate non-transparent plastic, even transparent plastic or ordinary glass, attenuation is also very large, so ultraviolet lamps must be made of high-purity quartz glass.