High nucleation densities and short incubation times of polycrystalline diamond films can be promoted by the de-glow discharge-surface interaction process as in situ surface pretreatment method. As a result of the pretreatment, a carbon nanophase film whose properties are strongly affected by the de-glow discharge deposition parameters is formed. At optimal conditions this nanophase has a predominant diamond character which promotes diamond growth in the subsequent chemical vapor deposition (CVD) process. In this work, the evolution of the diamond film during a standard hot filament (HF) CVD process, following the de-glow discharge pretreatment, was studied by nonreactive ion implantation of the precursor film and C-13 isotopic labeling during different deposition stages in addition to spectroscopic and high resolution scanning electron microscopic (WR-SEM) techniques. Our results indicate that only part of the diamond growth centers formed by the de-glow discharge process are placed on the surface but rather they are distributed homogeneously within the precursor film. Using (CH4-)-C-13 isotopic labeling it was shown that the nanodiamond films formed by the de-glow discharge process are stable under standard HF CVD conditions. Only a fraction of the nanodiamond particles deposited by the de-glow discharge processes serve as nucleation centers for the growth of diamond. A complex interlayer composed of a nanodiamond composite is formed between the silicon substrate and the microcrystalline diamond film.