The two colored glass samples were measured with a UV/Visible
spectrophotometer “Jasco” V-530 in an in-line transmission configuration.
The collected spectra in Fig. 2 present various optical responses
depending on the nature and the structure of NPs.
The transmission spectra contain the information about absorption
properties responsible of the colouring. These spectra obtained
after staining process present a SPR probably due to silver or copper
NPs growth [16,17]. The Beer-Lambert's law gives the T transmission
of the I flux for an incident I0 flux