Tuning of the surface plasmon resonance (SPR) band of Au-0 (587-611 nm) has been demonstrated by controlling the refractive index (1.8349-2.0006) of the encapsulating matrix in a new series of nano-Au-0-antimony glass (K2O-B2O3-Sb2O3) dichroic devitrified composites. They have been synthesized by a single-step melt-quench in situ thermochemical reduction technique without using any external reducing agent or additional processing step. Dichroic behavior is due to elliptical shape of Au-0 nanoparticles having 13-18 nm size range and aspect ratio about 1.2 according to transmission electron microscopic image. X-ray and selected area electron diffractions manifest the growth of (1 1 1) and (2 0 0) crystallographic planes of Au. (C) 2009 Elsevier B. V. All rights reserved.