Nanoparticulate silver thin films have been prepared on glass substrates by thermal evaporation and their surface modification was triggered by brief (<10 min) bromination carefully monitored ex situ using structural, microscopic and optical probes. X-ray diffraction reveals that this sample remains amorphous even after brief bromination which gave the crystallinity of Ag. The optical absorption of the samples manifests the surface plasmon resonance (SPR) phenomena, which is very sensitive to bromination time and also varies with Ag film thickness. The number density of Ag particles decreases even as their mean size increases upon bromination. Optimization of the bromination process of a new type of plasmonic material could lead to applications in sensor, SERS-active substrates and plasmonic technologies. (C) 2012 Elsevier B. V. All rights reserved.