Effect of partial substitution of K2O by MgO on the structure, and thermal, physical, optical properties and crystallization behaviour of K2O–MgO–B2O3–P2O5 glasses.

In this work, a series of K 2 O–MgO–B 2 O 3 –P 2 O 5 (KMBP) glasses were prepared by the melt-quenching method and the glass-ceramics were prepared by the one-step heat treatment. The thermal, structural, physical and optical properties, as well as the crystallization behaviour of the KMBP system, were investigated in detail using characterization techniques such as DSC, XRD, SEM, FTIR, transmittance spectroscopy and microhardness. As indicated by DSC, the thermostability and glass-forming ability were gradually enhanced through the partial substitution of K 2 O by MgO. XRD showed that the main crystalline phases of the glass-ceramics (GC) were gradually converted from the P –Mg–K–O based crystalline phases to the P –Mg–O based and the P –Al–O based crystalline phases. The SEM results indicated that tiny grain-like crystals were successfully precipitated from the parent glasses after heat treatment. The deconvoluted FTIR spectra results showed a gradual conversion of the [BO 3 ] and [PO 3 ] units towards the [BO 4 ] and [PO 4 ] units with the increase of the MgO contents. The increase in the degree of glass network polymerization was the essential reason for the increment in the microhardness of the parent glasses. The microhardness of GC featured a trend concordant with the crystallinity of the crystalline phases. The values of metallization criteria (M C) between 0.34 and 0.45, as well as the higher values of third-order nonlinear polarizability (χ (3)) and nonlinear refractive index (n nl) are indicative of the good suitability of the KMBP glasses for the nonlinear optical applications. [ABSTRACT FROM AUTHOR]