Photo-thermo-refractive glass (PTRG) is becoming one of the most important materials for holographic fabrication of diffractive optical elements. Using a two-step process large numbers of diffractive elements, such as filters, attenuators, switchers, modulators, beam splitters etc., can be fabricated in the interior of glass. SIMS, XPS and RBS were applied to study surface modification of PTRG after UV-irradiation and thermal development. SIMS elemental imaging provided information on surface clustering of some elements (Na,F) and depth profiling reveals formation of several layers of various compositions to a depth of about 8 micrometers. RBS provided a basis for quantification of PTRG composition and SIMS calibration. XPS was employed in order to obtain chemical bonding of the surface precipitates. RBS and SIMS were used to evaluate a diffusion barrier coating for the PTRG. A characterization protocol was developed for accurate quantification of many components of the PTRG to aid in glass production optimization.