Table 3.

Oscillation modes of the considered BPML glass series and the corresponding FTIR positions.

Peak position (cm− 1)	Oscillation mode
455	Bending vibrations of the bond, overlapping with bond vibrations, and also vibrational modes associated with Mg2+ ions
501,552	Vibrational modes associated with modifier cations, particularly Li+ ions.
618	Vibrational modes associated with bonds, overlapping with bending vibration
675	BO3 bending vibrations.
718	bending vibrations.
773	bending vibrations.
827	Stretching of tetrahedral BO4 groups.
877	Stretching vibrations of tetrahedral borate groups such as diborate in BO3.
951	The stretching vibrations in tetrahedral BO4 in di-borate.
1024	Stretching vibrations of in BO4 units from tri- tetra- and penta-borate groups.
1104	Stretching vibrations of tetrahedral borate groups such as penta-borate groups.
1205	stretching vibration of trigonal BO3 units in boroxol rings.
1268	Ascribed to the stretching vibration of triangular BO3 units.
1343	Stretching vibrations of BO3 triangles with non-bridging oxygens (NBOs) (stretching of in meta-borate, pyro-borate, and ortho-borate groups of BO3).
1392	stretching vibrations of BO3 units in meta-, pyro- and ortho-borate groups.
1455	Asymmetric stretching vibration of BO3 triangles containing non-bridging oxygens (NBOs).