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Formation of CuBr nanocrystals in fluorophosphate glass is investigated for the first time. The features of the nanocrystals nucleation and growth during isothermal treatment of the glass are analyzed based on spectral studies results. The mean size of the CuBr nanocrystals formed via thermo-induced crystallization varies within 7–10 nm. The nanocrystals size of 9 nm is revealed to be critical, below which the CuBr nanocrystals possess cubic structure, and above which the structure of the nanocrystals becomes hexagonal. While during spontaneous nanocrystals nucleation from the glass melt, without additional thermal inducing, the CuBr crystal structure remains cubic regardless of the size. A preliminary explanation of the effects revealed is proposed, assuming the principal role of internal pressure in drops of a copper halide liquid in a glass matrix.

Chromium-doped borate glass-ceramics are prepared at different temperatures via bulk crystallization of the borate glass matrix. The temperature influence on the spectral and operational characteristics of the material is observed. Rod-shaped LiAl7B4O17 crystals nucleate in a glassy matrix during two stage heat treatment. Borate glass-ceramics possess luminescence in the 650–800 nm region when excited with “green” light. An increase in the annealing temperature of glass-ceramics lead to several changes: (1) the luminescence quantum yield increase from 13% to 50%, (2) color coordinates of glass-ceramics luminescence shift towards to the red spectral region, (3) hardness and resistance to acid solutions of glass-ceramics increase. XRD experiments are carried out within the direct heating of a glass sample. The results show that the maximum size of nanocrystals was reached at a temperature of 600 °C, which coincided with the maximum of the exothermic region on the DSC curve. Thus, the spectral and operational properties of borate glass-ceramics exceed those of the initial borate glass, which makes borate glass-ceramics doped with chromium ions promising material for creating red and near infra-red emitters .

An unexpected sequence of forming different crystal lattices for the CuCl nanophases in potassium aluminoborate glass depending on the preceding heat treatment temperature is revealed. The hexagonal wurtzite-like nanocrystals are shown to crystallize from the liquid CuCl nanosize droplets separated at the lower heat treatment temperatures (380 °C to no more than 400 °C) than in the case for the cubic sphalerite-like CuCl nanocrystals (higher than 400 °C). This sequence is inverse with respect to the standard temperature sequence of crystallizing the bulk hexagonal and cubic phases from a melt that is known for both CuCl and its structural prototype, ZnS. A tentative explanation for the effects revealed is proposed, the explanation assuming the principal role of internal pressure in the CuCl nanodroplets in setting the location of a phase point at the phase diagram.

Alkali-alumina-borate glass-ceramics doped with Cr3+ ions are successfully synthesized by the melt quenching technique. LiAl7B4O17:Cr3+ nanocrystals are formed in the glass host during the subsequent one- and two-stage isothermal treatments above the crystallization temperature of the nanophase. For the samples of the initial and heat-treated glass, absorption spectra are obtained containing two absorption bands that are shifted to the short-wave region after the heat treatment. The impact of the electron flux (absorbed dose of 300 kGy) leads to an increase in the optical density and color center formation. There are a wide emission band appears in the blue-green region of the spectrum (λ = 463 nm), the nature of which is possibly due to the luminescence of the borate host and series of R lines in the chromium ions in the cathodoluminescence (CL) spectra of heat-treated glass-ceramics. The optimal annealing time is determined at which the maximum value of the absolute quantum yield reaches of ≈ 40%. The luminescence decay kinetics at 463 nm is fitted by the sum of the exponential and the hyperbolic approximation. The decay time for all samples is about 200 µs. In the red spectral region (λmax = 699 nm), the luminescence decay kinetics is complex and is described by the sum of 3 exponentials and a second-order hyperbola with decay times of 0.3; 5 ± 1 ms; 10 – 27 ms, respectively. The dynamics of the growth of the decay time with increasing annealing time is manifested. Issues related to the nature of possible processes after pulse electronic excitation are discussed.

A series of new fluorophosphate glasses with small content of phosphates doped with various Nd3+ ions concentration for optical applications has been prepared and characterized. Based on Judd-Ofelt intensity parameters, radiative transition probability, radiative lifetime, branching ratio, and emission cross-section of Nd3+ions have been derived for all Nd3+concentrations.The effect of the glass rigidity and lead presence in glass composition on radiative properties have been estimated. The high emission cross-section (2.33×10−20 cm2) and large quantum efficiency (93%) both suggest the glass potential for compact 1.06-μm laser applications. The analysis of luminescence kinetics has shown the formation of neodymium ion clusters beginning from neodymium concentration of 1.006 × 1020 cm−3.

Phosphate glass with a high transmission level in the visible and near-IR spectral regions doped with a high cerium concentration (up to 25 mol%) was synthesized and experimentally investigated in terms of applicability as a material for magneto-optical devices. Glass transition temperature was 590 °C. Glass refractive index varied between 1.5831 and 1.5884 depending on cerium content. The structure of the glass obtained was mostly metaphosphate with admixture of ultraphosphate complexes. It is shown that the maximum values of Verdet constant (11 rad/T/m at 1064 nm) are reached with increasing cerium concentration up to 25 mol%. The analysis proves the viability of the studied glass to create optical elements using the Faraday effect.

Alkali alumina-borate glass-ceramics doped with different concentration of Cr3+ ions was prepared by conventional melt-quenching technique. Luminescent glass-ceramics was derived by volume crystallization of the precursor glass via two-stage heat treatment. The phase transition temperatures, structure, spectral and luminescent properties of the glass-ceramics were determined by differential scanning calorimetry (DSC), X-ray diffraction (XRD), optical absorption, photo- and cathodoluminescent spectroscopy. The XRD studies revealed the LiAl7B4O17: Cr3+ nanocrystals nucleation (mean size of 20–23 nm) during the heat treatment. The photoluminescence spectra consisted of three intense bands in the 685–715 nm region. The maximum quantum yield value under 532 nm excitation was 30%. The difference between photoluminescence (PL) and cathodoluminescence (CL) decay kinetics is presented and possible nature of this phenomenon is discussed.