The peak at -36.3 ppm observed in the pure inorganic glass spectrum can be assigned to Q 3 tetrahedron containing three bridging oxygens and one terminal P=O. This peak decreases in intensity in the blend samples, which could suggest a strong polarisation of the P=O bonds to the Zn centres in the blends, again resulting in a shift of their 31 P NMR signal. The pure glass 31 P spectrum also shows additional peaks between 0 and -11 ppm, which are in the region of Q 0 (0 ppm) and Q 1 tetrahedra (-11 ppm). The origin of these peaks likely correlates to adventitious hydrolysis of the glass, depolymerising the glass network over time. Only one of these peaks (Q 1 at -10.7 ppm) is present in the blend spectra, with negligible shift.