Non-centrosymmetric π-conjugated systems incorporating closo-dodecaborate clusters, [NC–C₆H₄–C(H)N(H)–B₁₂H₁₁]⁻ (2), [NC–C₆H₄–C(H)C(H)–C₆H₄–C(H)N(H)–B₁₂H₁₁]⁻ (3), and [NC–C₆H₄–C(H)C(H)–C₆H₄–C(H)C(H)–C₆H₄–C(H)N(H)–B₁₂H₁₁]⁻ (4) have been synthesized by reaction of the monoamino derivative of B₁₂, [B₁₂H₁₁NH₃]⁻ (1), with various arylaldehydes, R–C₆H₄–CHO. These Schiff base-like compounds were fully characterized by multinuclear NMR spectroscopy and mass spectrometry. In order to evaluate these boron rich π-systems as potential materials for two-photon absorption (TPA) processes, UV linear absorption curves were recorded for 3 and 4, and comparatively studied with those of the boron-free π-systems NC–C₆H₄–C(H)N–CH₃ (5) and NC–C₆H₄–C(H)C(H)–C₆H₄–C(H)N–CH₃ (6). The donor effect of the boron cluster was evidenced by a shift to the lower energy of the absorption band in the spectra of systems incorporating B₁₂. The two photon absorption (TPA) spectrum of compound 3, obtained by the up-conversion method, shows a resonance at 720 nm with a cross-section σ_TPA of 35 × 10⁻⁵⁰ cm⁴ s photon⁻¹ molecule⁻¹. This value suggests the potential of B₁₂ clusters to be used as new donor groups for the synthesis of non-linear materials.

Optical Frequency Domain Reflectometry (OFDR) is used to make temperature distributed sensing measurements along a fiber by exploiting Rayleigh backscattering. This technique presents high spatial and high temperature resolutions on temperature ranges of several hundred of degrees Celsius. With standard telecommunications fibers, measurement errors coming from the correlation between a high temperature Rayleigh trace and the one taken as a reference at room temperature could be present at extremely high temperatures. These correlation errors, due to low backscattering signal amplitude and unstable backscattering signal, induce temperature measurement errors. Thus, for high temperature measurement ranges and at extremely high temperatures (e.g., at 800 °C), a known solution is to use fibers with femtosecond laser inscribed nanograting. These fs-laser-insolated fibers have a high amplitude and thermally stable scattering signal, and they exhibit lower correlation errors. In this article, temperature sensing at 800 °C is reported by using an annealed zirconia-doped optical fiber with an initial 40.5-dB enhanced scattering signal. The zirconia-doped fiber presents initially OFDR losses of 2.8 dB/m and low OFDR signal drift at 800 °C. The ZrO₂-doped fiber is an alternative to nanograting-inscribed fiber to make OFDR distributed fiber sensing on several meters with gauge lengths of 1 cm at high temperatures.