The glass of 12.5Li2O-50GeO2-37.5P2O5 composition was synthesized by melt quenching. By means of its thermal annealing, single-phase LiGe2(PO4)3 composition was obtained, which is promising as a solid electrolyte for all-solid-state lithium-ion power sources. Using total X-ray scattering with analysis of the pair distribution function, and diffuse reflectance spectroscopy in the UV-Vis range, the local structure and optical properties of initial (amorphous) glass and crystallized glass were studied. An assessment of the influence of the effect of glass crystallization on these properties was carried out. It has been shown that structuration in the glass is observed only at the level of the first-second coordination sphere of Ge and P atoms. From the optical absorption spectra of the initial glass, the presence of F+ centers in the glass has been revealed, and their concentration decreases as a result of glass crystallization. The estimated value of the band gap for the crystallized glass, i.e. for the LiGe2(PO4)3 phase, is 6.15 eV for the case of direct allowed transitions, which exceeds the calculated value known from the literature by approximately 2 times.