Preparation of 2,5-diphenyloxazole doped sol-gel glasses and their application to radio-analytical chemistry

Transparent, colourless, monolithic sol-gel glasses doped with 2,5-diphenyloxazole (PPO) at different concentrations were prepared via the polymerisation of tetraethyl orthosilicate (TEOS) in a H 2 O-AcOH-EtOH-PPO solution. The gel samples were aged at room temperature, and dried in two stages: first at room temperature, then at 70°C to reduce possible fracture. They have pore diameters in the range 1.8-2.1 nm. The leaching of PPO from the sol-gel glass was monitored using ultraviolet (UV) and X-ray photoelectron spectroscopy (XPS). The results show that the sol-gel glasses dried at the higher temperature leach less than those dried at room temperature. These sol-gel glasses, either in monolith or powder form, are effective in detecting β – radioactivity.