Intermediate-range order in Organic Glasses

Intermediate-range order (IRO) is a unique phenomenon of glasses. An important structural signature of the IRO is the so-called first sharp diffraction peak (FSDP) that appears at a low scattering vector position (< 2Å-1) of the X-ray or neutron scattering patterns of the glasses. Although FSDP has been observed in many different glass systems, its structural origin remains elusive and seems to be specific to individual glass systems. The IRO has been studied extensively in inorganic glasses but very few efforts have been dedicated to organic glasses. In this paper, we select a simple organic glass system(i.e.,polystyrene) as a model system to understand the effect of molecular weight and temperature on the FSDP. We also study the effect of radiation on the FSDP using neutron radiation generated from the 4.5-MV tandem accelerator at Ohio University. The effect of radiation dose on the FSDP will also be discussed.