Transmission Mossbauer spectroscopy (TMS) and conversion electron Mossbauer
spectroscopy (CEMS) have been used to obtain spectra of Sn-119 in three co
mmercially produced soda-lime-silica float glasses. Measurements have been
made of the f-factor of both tin oxidation states from a series of results
at temperatures between 290 and 13 K. TM spectra yielded data on the whole
tin layer, which extends to a depth of about 20 mu m, while CEM spectra gav
e information on the near-surface region with a depth of about 2 mu m. The
isomer shift and quadrupole splitting of Sn4+ in the near-surface were high
er than the shift and splitting measured for the whole region, and the Deby
e temperature, theta(D), was found to be significantly less in the surface
than in the full depth containing tin, showing that it was less tightly bou
nd. The shift, splitting and Debye temperature of Sn2+ remained the same th
roughout the glass surface within experimental errors. These results are di
scussed in terms of the conditions of the float process and differences in
the coordination number of Sn4+. (C) 1998 Published by Elsevier Science B.V
. All rights reserved.