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This paper reports the first spectroscopic demonstration of photoluminescence ͑PL͒ owing to plasmon resonance energy transfer ͑PRET͒ from silver nanoparticles ͑NPs͒ to luminescent species in glass. Optical absorption and PL spectroscopy experiments performed on the melt-quenched silver-doped glass indicate the presence of single Ag + ions, Ag + -Ag + and Ag + -Ag 0 pairs, and Ag NPs. After thermal processing of the material, nonradiative energy transfer from the Ag + -Ag 0 luminescent centers to Ag NPs is observed by uniform suppression of band emission and the vanishing of the excitation band associated. Furthermore, evidence for PRET is observed after glass heat treatment by the appearance of a new excitation band near the surface plasmon resonance peak of Ag NPs at about 420 nm, when emission of silver pairs is monitored around 550 nm. In fact, excitation at 420 nm leads to a band emission centered around 530 nm indicating that the excitation of luminescent silver species indeed takes place via PRET. The luminescence is interpreted as arising from a Ag NP→ Ag + -Ag 0 → Ag + -Ag + energy transfer scheme.

Experimental evidence indicates that bainitic ferrite formed by transformation at low temperatures (200-350ºC) contains quantities of carbon in solid solution far beyond those expected from para-equilibrium. A change in the conventional symmetry of the bainitic ferrite lattice from cubic to tetragonal explains the abnormal solid solubility detected. This carbon supersaturation was measured by atom probe tomography, and the tetragonality of the bainitic ferrite, was characterized by means of X-ray diffraction analysis and high resolution transmission electron microscopy.

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