Optical basicity
Optical basicity of the host glasses is an important structural
factor affecting the valence and coordination states of the transition
metal ions in the glasses. This is especially evident in the case
of Cr-doped alkali-borate glasses [9]. In our glassy backbone, there
is definitely different coordination around chromium ions; Cr+ ions
can either be surrounded by boron, alkali and halide ions. The optical
basicity can be accessed experimentally but the applicability of
the method is rather limited.