The quaternary alloy In0.48(Ga1−xAlx)0.52P, lattice-matched to GaAs, has a direct band gap transition in the wavelength range of green-red light and is useful in optoelectronic applications such as visible light emitting diodes and laser diodes. We have investigated a set of six nominal In0.48(Ga1−xAlx)0.52P layers that were grown on GaAs (001) by low pressure metalorganic chemical vapor deposition (MOCVD) turbo disk technology. In order to control and optimize the growth conditions to produce high quality InGaAlP epilayers, a variety of nondestructive techniques, including photoluminescence (PL), Raman scattering, photoreflectance (PR), reflectance anisotropy (RA) spectroscopy, atomic force microscopy (AFM), and high resolution x-ray diffraction (HRXRD) have been applied to evaluate the epitaxial films and growth processes. HRXRD confirmed a good lattice match between the epilayers and the substrate material. The PL and PR spectra showed the variations of the InGaAlP PL peak and the energy band with growth pressure and other parameters. Raman spectral line shape analysis leads to information about the sample crystalline quality. Polarization dependent PR and RA spectroscopy were used to detect the in-plane anisotropy of epitaxial materials. AFM was used to study the surface morphology of these quaternary compounds and to nondestructively detect any possible dislocations in these hetero-epitaxial materials. The optimized parameters for the growth of high quality InGaAlP films on GaAs were obtained. The combination of these nondestructive techniques offers a better understanding of MOCVD-grown In0.48(Ga1−xAlx)0.52P/GaAs and a useful way to optimize the growth parameters of high quality quaternary semiconductor materials.