I was faced with the following phenomenon at the production of laser glass,.
The glass may have both a pink color (by the light of a filament lamp (file 1)) and a bluish color (by the light of a diode lamp (file 2)).
This phenomenon is observed only in neodymium phosphate glasses which niobium oxide is present.
What reasons can change color?
And is there any literature which describe this phenomenon ?
Thank You for Your attention.