Tellurite glasses exhibit strong non-linear properties which are related to the asymmetric environment of the Te atom. The non-linear optical effects are strongest when the Te atoms are four-coordinated with oxygen, in the pure TeO2 glass, and decrease as three-coordinated Te form with the addition of a modifier. However, unlike many tellurite glasses, indirect structual analysis has shown that the tellurium environment does not change with the addition of TiO2. This experiment proposes to use a combination of neutrons and X-rays to determine the Te-O and Ti-O environments, and determine how the glass structure varies with composition.