We studied the property adjustments of polymers such as PMMA poly(methylmethacrylate) and PMMI poly(methylmethacrylimide) for optical waveguide applications. The standard generic process to yield ridge waveguides requires the PMMA to undergo thermal treatment to avoid worm-like defects. We analysed the occurrence of these defects and found a solution to make the PMMA strengthened to pass the whole process. Then, the optical losses of both the polymers are investigated at two wavelengths and with two methods. Finally, small singlemode ridge waveguides are produced with mode diameters around 3-4 μm and linear optical losses ~1-3 dB/cm at 1550 nm. The index contrast is sufficiently high to perform, for example, wavelength micro-ring resonators based filters.