The effect of tin fluorophosphate-glass (Pglass) nanoparticles on the polyamide-6 (PA6) matrix in Pglass/PA6 hybrids has been investigated by C-13 solid-state nuclear magnetic resonance (NMR). The crystallinity determined by direct-polarization C-13 NMR combined with longitudinal relaxation-time (TIC) filtering varied between 31 and 44%. T-1C-filtered C-13 spectra with cross polarization clearly showed resonances of both the alpha- and gamma-crystalline phases of PA6, typically at ratios near 45:55, while the similarly processed neat polymer contained only the a-phase. This suggests that the Pglass promotes the growth of the gamma-crystalline phase. (c) 2008 Wiley Periodicals, Inc.