Bioceramic coatings with defined chemical composition and structure are often needed to satisfy specific biocompatibility properties in the prosthetic field. An example is hydroxyapatite (HA) for coatings, which, according to the Standard Specifications of the ASTM, must be crystalline and have a stoichiometric molar ratio Ca/P=1.67 with a 95% minimum amount of HA. Since the methods (plasma flame spray, ion beam sputtering, etc.) to obtain bioceramic coatings, in particular those for HA, induce changes in the chemical composition, structure and physical state of the coating, an alternative and innovative method (the so-called polymeric route) which provides bioceramic coatings under less severe conditions with controlled chemical composition and structure, was used in this work. The method was applied to the preparation not only of HA, but also, for the first time, of high-temperature-melting calcium phosphate bioactive glasses with a molar ratio CaO/P2O5=1 (calcium metaphosphate) and in the range 1–1.5 (calcium oligophosphates). The different phases of the process were characterized by vibrational FTIR spectra. The structure of the final glasses were also studied by Raman spectroscopy and compared with the spectra of the same products obtained by the traditional melting method.

A non-destructive 'in situ' Raman spectroscopic study was carried out on 28 artistic glasses grouped in eight age classes between 1750 and 1940, in order to characterize the authenticity (age) of these objects. Other non-'in situ' instrumental methods which require only micro amounts of sample, should be avoided in this ease owing to the great brittleness of the samples. Although it was not found possible to characterize the age of the samples from the Raman spectra, which were very similar for all the different glasses examined, nevertheless, the intensity of the fluorescence band increased with the age of the samples. The logarithm of the ratio between the 1880 cm(-1) Raman band intensity and that of the fluorescence band, obtained from the spectra where the fluorescence band was kept at the same intensity for the different samples, shows a linear relationship with the age of the glasses, and therefore constitutes a spectroscopic marker for the characterization of the authenticity of the samples.