Time resolved electron paramagnetic resonance (TREPR) spectroscopy has been used to investigate the magnetic and kinetic properties of monoradicals covalently bound to silicon oxide surfaces. Norrish I alpha-cleavage of aliphatic ketones and photoreduction of aromatic ketone n,pi* triplet states were used to produce the radicals. The ketones were anchored to the silica surface via a chlorosilane-terminated alkane chain. The aliphatic ketones were analogues of di-tert-butyl ketone, and the aromatic ketones were benzophenones connected at the ortho, meta, and para positions. A detailed description of the synthesis, attachment, and characterization procedures is given for all surface-anchored ketones. Comparison to TREPR spectra of similar structures in free solution shows that both radical pair (RPM) and triplet (TM) spin polarization mechanisms are affected by anchoring the molecules to the surface. Stronger TM polarization is observed in all cases, and increases in the line width are observed when the "tether" chain length is less than five carbon atoms. Longer tethers show line widths similar to those observed in free solution. Polar solvents at the interface also affect the ratio of RPM to TM polarization. The T-1 of the surface-bound radicals increases in some cases. These changes are discussed with respect to the rotational correlation time of the radicals and the "effective viscosity" at the interface. The ortho-alkylated benzophenone exhibits a long-lived EPR signal which may be due to a "photo-enol" type biradical, rather than monoradicals from the photoreduction process. Signals from the para-alkylated benzophenone show evidence for a spin-correlated radical pair (SCRP) at very early delay times.