Dear Recep Kurtulus

We can predict the colorization / discoloration of radiation shielding glass after exposure to the radiation source if the composition and presence of impurities in the glass are known.

The intensity and color of the glass coloring depends on the composition of the glass and the radiation dose.

Gamma rays and neutrons color the glass along the entire thickness.

α-particles and β-rays penetrate into the glass to a small depth and the glass color occurs only in the surface layers.

All types of radiation lead to the formation of free electrons and excited atoms in the glass.

If there are ions in the glass that can change their valence, the mechanism of changing the color of the glass can be explained by the addition or recoil of electrons.

I wish you success.

Dear Yuri S. Pavlov

I'd like to thank you for your detailed explanations.

For the composition of the glass point, the existence of ions, i.e. iron (II) oxide, can lead to the change in color after radiation exposure. As iron (II) oxide causes a greenish-yellowish hue, then this glass body's color will turn into a sharp greenish-yellowish color? Or the combination of color resulted from glass composition and radiation dose?

Hope that I understand your explanations in the correct way.

Dear Recep Kurtulus, your thoughts are on the right track!

The color and intensity of the color is determined not only by the presence of specific ions, but also by their combinations, for example, impurities of variable valence, which play the role of electron traps (acceptors) in radiation processes: Ce4+, Fe3+ and Eu3+.

For example, transitions, which change the valence and causes changes in the color of the glass: V3+ (green) + е- → V2+ (pink).

In the case of Ce4+, Ce5+, Sb 5+ and Pb2+ ions, the change in valence does not cause a change in the color of the glass: Ce4+ (colorless) + е- → Ce3+ (colorless).

In your case with iron, you need to know exactly which ions, what valence, in what quantities and in what combinations are involved in the coloring process. Accurate calculation is possible, but not so easy.

Radiation processing for glass coloration / discoloration

Glass is particularly susceptible to radiation-induced coloration/ discoloration due to its amorphous, non-crystalline structure. The nature of the optical changes varies, but usually consists of coloration in the visible light region and the formation of absorption bands in the infrared and/or ultraviolet regions. The optical density is almost always increased. It is well documented, for example, that high doses of gamma radiation turn glass various shades ranging from deep brown to pale amber [Prasil, 1991]. Clear glass discolors when exposed to gamma irradiation, such as from a Cobalt-60 source. Ordinary flint, borosilicate, and lead glass undergo a color change from clear to light amber, brownish to black, depending on the amount of energy absorbed. Milk glass, when exposed to gamma irradiation, yields a grayish color, depending on energy absorbed and any swirling effect is highlighted, probably due to concentrations of color in the glass that have not mixed uniformly. The actual mechanism of the formation of “color centers” has been described [Prasil, 1991]. The final color created is dependent on the chemical composition of the glass and can be altered by selection of additives (e.g., cerium ions can reduce browning; manganese ions induce an amethyst color). Final color is a combination of original glass color and the effects of color center formations. Color from irradiation is considered metastable and heat, for example, is known to reverse the effect. Depending on the type of color centers formed and the hardness of the glass, varying amounts of heat or energy penetration are required to reverse color.

https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=&cad=rja&uact=8&ved=2ahUKEwjP_NvZqfbxAhWyzDgGHS-mBJ4QFjACegQIHhAD&url=http%3A%2F%2Fcdn.intechopen.com%2Fpdfs%2F32110%2FInTech-Glass_as_radiation_sensor.pdf&usg=AOvVaw2AEO3woBgZ6rXawctpTM5q

Yes, you are thinking right. It depends upon the dye/coloring material in the glass. Exposing a colored glass to different doses of radiation usually fading occurred. this change in color intensity in term of de-colorization can be measured using UV-VIS spectrophotometer. The colored polymers are in usual use in estimation of radiation doses and you can search in literature relating to radiation dosimetry using solid polymeric strips.

Dear M.M. Mahfuz Siraz and Ashfaq Ahmad Khan

I appreciate your valuable comments. I will definitely consider them to understand the changes in color.

it depend on the time

Dear Mengge Dong

Can you please explain more about time? At least how much time do we need to observe color change?