Abstract
The influence of temperature on the optical and structural properties of three samples of polypropylene fibres (having different deniers) has been studied over the temperature range (28–67
oC). A hot-stage attached with the Pluta microscope has been modified for this purpose. The effect of temperature on the refractive indices (
n
∥,
n
⊥), the mean polarizabilities per unit volume (
P
ll,
P
⊥) and the optical orientation function
f(θ) have been investigated for each sample. The thermal coefficients of the refractive indices were determined. The refractive index profiles are also provided at different temperatures for each of the three tested samples. Microinterferograms are given for illustration.