  We report on the optical and structural properties of plastic scintillators
irradiated with neutron beams produced by the IBR-2 reactor of the Frank
Laboratory of Neutron Physics in JINR, Dubna. Blue UPS-923A and green plastic
scintillators were irradiated with neutron fluence ranging from 10$^{13}$ to
10$^{17}$ n/cm$^2$. Discolouring in the plastic scintillators was observed
after irradiation. The effects of radiation damage on the optical and
structural properties of the samples were characterized by conducting light
yield, light transmission, light fluorescence and Raman spectroscopy studies.
The results showed that neutron radiation induced damage in the material. The
disappearance of the Raman peak features in green scintillators at frequencies
of 1165.8, 1574.7 and 1651.2 cm$^{-1}$ revealed significant structural
alterations due to neutron bombardment. Losses in fluorescence intensity, light
yield and light transmission in the plastic scintillators were observed.

Instrumentation and Detectors