In the present book optical and thermal properties of some amorphous materials like polymers, graft copolymers and glasses have been discussed detail. The first part of the book (Chapter 3) gives an introduction of polymeric materials including their classification schemes, methods of graft copolymerization and potentiality of Photoacoustic Spectroscopy (PAS) technique over other technique for studying the two -phase systems. In the second part of the book (Chapter 4) variation in thermophysical properties of these PMMA-g-PC copolymers with grafting of PMMA have been made. A direct relation between the grafting percentage and thermal diffusivity of copolymers has also been developed. This relation has been fitted in the experimental data points and the computer analysis of the fitting justifies the applicability of the empirical relation for PMMA-g-PC copolymers. Third part of the book (Chapter 5) discusses the photoacoustic study of some Zinc phosphate glasses with doping of Nd2O3. The thermal diffusivity, optical absorption coefficient and energy band gaps for zinc-phosphate glass samples has been calculated by the photoacoustic phase shift method.