Mechanical properties of resorbable calcium-phosphate glass optical fiber and capillaries

Calcium-phosphate glass optical fiber and capillaries (with composition identical to the core and the cladding of the fiber) were fabricated and subjected to mechanical characterization. Tensile tests were carried out to determine the strength distribution, the fatigue behavior and the elastic modulus of fibers and capillaries. The tests were performed without the application of any coating, in order to assess the behavior in bare conditions, just like in the provisional application as bio-resorbable elements. Strength ranging from 200 to 350 MPa was measured for both fiber and capillaries, the Weibull's modulus being around 3 to 6, thus revealing quite scattered distributions associated to the presence of variable surface flaws. The elastic modulus of the two glasses was shown to depend on the specific composition, the presence of MgO being responsible for a stiffer material. An evident sub-critical crack growth was also pointed out in the presence of water.