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An Eu3+‐doped novel mother glass in the K2O–SiO2–Y2O3–Al2O3 (KSYA) system was prepared by the melt‐quench technique. The transparent Y3Al5O12 (YAG) glass–ceramics were derived from this glass by a controlled crystallization process. The formation of YAG crystal phase, size and morphology with the progression of heat treatment was examined by X‐ray diffraction (XRD), transmission electron microscopy, field‐emission scanning electron microscopy, and Fourier transformed infrared reflectance spectroscopy. The crystallite sizes obtained from XRD are found to increase with heat‐treatment time and vary in the range of 35–45 nm. The photoluminescence spectra of Eu3+ ions exhibit emission transitions of 5D0→7Fj (j=0, 1, 2, 3, and 4) and its excitation spectra show a charge transfer band around 280 nm. From these emissions, the site symmetry in the vicinity of Eu3+ ions has been found to be Cs or lower than Cs in the nanoglass–ceramics. Absorption and fluorescence spectra reveal that the Eu3+ ions are entering into the YAG nanocrystals of the glass–ceramics. The present study indicates that the incorporation of Eu3+ ions into the YAG crystal lattice enhance the fluorescence performance of the nanoglass–ceramics. We believe that this work would generate new avenues in the exploration of YAG nanoglass–ceramics in particular and other glass–ceramics of very high‐temperature melting crystals in general.

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The precursor glass in the ZnO-Al 2 O 3 -B 2 O 3 -SiO 2 (ZABS) system doped with Eu 2 O 3 was prepared by the melt-quench technique. The transparent willemite, Zn 2 SiO 4 (ZS) glassceramic nanocomposites were derived from this precursor glass by a controlled crystallization process. The formation of willemite crystal phase, size, and morphology with increase in heat-treatment time was examined by X-ray diffraction (XRD) and field-emission scanning electron microscopy (FESEM) techniques. The average calculated crystallite size obtained from XRD is found to be in the range 18-70 nm whereas the grain size observed in FESEM is 50-250 nm. The refractive index value is decreased with increase in heat-treatment time which is caused by the partial replacement of ZnO 4 units of ZS nanocrystals by AlO 4 units due to generation of vacancies. Fourier transform infrared (FTIR) reflection spectroscopy was used to evaluate its structural evolution. Vickers hardness study indicates marked improvement of hardness in the resultant glass-ceramics compared with its precursor glass. The photoluminescence spectra of Eu 3+ ions exhibit emission transitions of 5 D 0 ? 7 F j (j = 0, 1, 2, 3, and 4) and its excitation spectra show an intense absorption band at 395 nm. These spectra reveal that the luminescence performance of the glass-ceramic nanocomposites is enhanced up to 17-fold with the process of heat treatment. This enhancement is caused by partitioning of Eu 3+ ions into glassy phase instead of into the willemite crystals with progress of heat treatment. Such luminescent glass-ceramic nanocomposites are expected to find potential applications in solid-state red lasers, phosphors, and optical display systems. J ournalchanges which happen around the Eu 3+ ion sites in the glass host during crystallization because of its quite simple electronic energy levels. 25,26 The probing luminescent properties of Eu 3+ ion originate from the f-f electronic transitions in the 4f 6 electronic configuration that occurs from the excited level ( 5 D 0 ) down to lower levels ( 7 F j ) through the channels: 5 45 K. Binnemans and C. G€ orller-Walrand, "

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