Answered By: Regan Brumagen
Last Updated: Jul 19, 2016     Views: 520

From Dr. Robert Brill, Research Scientist Emeritus:

There are several elements that will cause common glasses to fluoresce.  The fluorescent response depends on several factors: primarily the elements present, sometimes matrix effects, the concentrations, the wavelength of the exciting radiation, the intensity of the exciting radiation, possibly the redox state of the elements, colorants that might be present, etc.
Leaving out the exotic elements not found in ordinary glasses, the responses are more-or-less as follows:
U (Uranium)-- A very strong bright-green response.  The color of the glass itself in visible light is usually a bright yellow or yellowish-green, or an amber color in a lead matrix.   You can tell a uranium-containing glass just by looking at it.  Once you have seen the color, you will remember it.  The color is usually obtained  by adding ~0.5 % U2O3.  Ancient glasses contain at most a few ppm of U --  not nearly enough to cause any UV fluoresence.
Pb (Lead) -- A strong icy-blue response, but not normally as strong as U.  The fluroescence is visible under both long-wave and short-wave UV.  High-lead glasses are usually colorless.  The fluorescence becomes noticeable at a level of about 5%,  and is strong by about 10-15%.  Pb normally fluoresces more strongly  than manganese or antimony.  (Don't mistake the reflection of visible purple light from the UV lamp for Pb fluorescence.  The Pb fluorescence is an icy-blue color and eminates from within the body of the glass.)
Mn (Manganese) -- A moderately strong "lemonade-like" greenish-yellow, often somewhat turbid.  This is usually not at all a strong  fluorescence.  Mn usually requires a level of ~ 0.5% (?) to be readily visible.  The greenish-yellow might be absorbed by the purple color of the body of the glass itself.  (Oxidized Mn is a purple colorant.)
Sb (Antimony) -- A bluish, whitish often rather weak fluorescence.  It may be obscured by other fluorescent species or colorants.

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