Glasses and Optical Materials: Current Issues and Functional Applications: On-Demand Oral Presentations
Sponsored by: ACerS Basic Science Division, ACerS Glass & Optical Materials Division
Program Organizers: Jessica Rimsza, Sandia National Laboratories; Delia Brauer, Otto Schott Institute of Materials Research
Friday 8:00 AM
October 22, 2021
Room: On-Demand Room 4
Location: MS&T On Demand
Invited
Fracture Toughness of Zeolitic Imidazolate Framework Glasses: Morten Smedskjaer1; Theany To1; Søren Sørensen1; Tao Du1; Yuanzheng Yue1; Mathieu Bauchy2; 1Aalborg University; 2University of California, Los Angeles
Metal-organic frameworks (MOFs) are a class of organic-inorganic hybrid materials with high porosity. Recently, it has been discovered that a subset of MOFs, namely zeolitic imidazolate frameworks (ZIFs), can be melted and quenched into glasses. This makes it possible to prepare bulk, transparent ZIF glasses with modifiable organic and inorganic building units. To enable their applications, there is a need to understand the mechanical properties. In this work, we study the fracture toughness (KIc) of ZIF glasses using both experiments and reactive molecular dynamics simulations. Although the glasses exhibit pronounced ductility at the nanoscale, we find that KIc is on the order of 0.1 MPa m0.5, which is even lower than that of brittle oxide glasses. We ascribe these phenomena to the preferential breakage and switching of the weak coordination Zn-N bonds. The observed Zn-N bond switching mechanism is found to be more pronounced for smaller organic linkers.
Viscoelastic Relaxation in Silica via Reactive Molecular Dynamic Simulations: Jessica Rimsza1; Scott Grutzik1; 1Sandia National Laboratories
Silica glass can exhibit rate dependent effects during elastic deformation, termed viscoelasticity. To explore this phenomena, reactive molecular dynamic simulations of silica glass using the ReaxFF forcefield were performed. Silica glass structures with a slit crack were loaded through application of far field loading and allowed to relax over time and at varying temperatures (300K, 600K and 900K). Defining viscoelastic behaviors including stress relaxation over time and temperature dependence were evaluated and changes in the glass structure were quantified, both globally and as a function of distances from the crack tip. Results were used to identify the type of structural transitions that are tied to viscoelastic relaxation and how they may factor in the slow crack growth process. Finally, the influence of water and composition on viscoelastic relaxation were explored.
Growth Optimization of Single Crystal Fibers from Polycrystalline Source Rods Using Laser Heated Pedestal Methods: Dolendra Karki1; Edward Clover Hoffman1; Paul R. Ohodnicki1; 1University of Pittsburgh
Because of their higher melting point than silica fibers, single crystal (SC) fibers offer sensing at higher temperature environment (~20000C). Laser heated pedestal growth (LHPG) utilizes high power (~15 Watt) CO2 laser to melt the tip of the SC source rod to grow such fibers from the melt. Since it is a crucible-free growth process, it offers purest of material composition along with the capability of growing smaller core-diameter fibers and controlled atomic composition. To our knowledge, mostly the single crystalline source-rods of same material are being used to feed the material for fiber growth. Here, we present the growth optimization to address challenges during SC fibers growth from polycrystalline source-rods of alumina, YAG and Nd:YAG, popular materials for high temperature sensing to fiber-laser applications. This approach would reduce the cost of SC fibers manufacturing as polycrystalline feed stocks are cheaper alternatives than the single crystalline ones.
Novel Oxide Glasses Via Non-traditional Processing: Adam Floyd1; Vinh Nguyen2; Daniel Rhonehouse2; Robel Bekele3; Jason Myers2; Daniel Gibson2; Shyam Bayya2; Rick Kim2; Jesse Frantz2; Jasbinder Sanghera2; 1Jacobs Technology, Inc; 2U.S. Naval Research Laboratory; 3University Research Foundation
Novel oxide glasses have been demonstrated through the use of non-traditional processing techniques. The non-traditional oxide glasses created using these processes have demonstrated exceptional properties due to the diverse and unique structures that can be formed. In addition, the kinetics of these processes have allowed formation of glasses with high concentrations of rare earth oxide that can act as a host to enable laser materials. We will discuss our recent efforts in developing novel passive and active glasses for use in IR laser applications and Vis/IR Gradient Index (GRIN) optics. Information on optical, physical, thermal, thermodynamic and mechanical properties as well as laser performance data will be presented.
Comparison of Spinel Produced by SPS and Traditional Pressing Techniques: Adam Floyd1; Noor Qadri2; Bryan Sadowski1; Guillermo Villalobos2; Shyam Bayya2; Rick Kim2; Syed Qadri2; Jasbinder Sanghera2; 1Jacobs Technology Inc.; 2U.S. Naval Research Laboratory
Transparent magnesium aluminate spinel (MgAl2O4) ceramic is a rugged window material that has excellent transmission from the UV to mid-wave IR. Traditional processing of spinel has required multi step processing using either vacuum sintering or hot pressing (HP) followed by hot isostatic pressing (HIP) to produce a fully dense body with the desired properties. Spark plasma sintering (SPS) has been shown to be a successful alternative to produce fully dense spinel samples with fewer steps and faster processing times. We will discuss some recent efforts to produce high quality spinel using SPS for use in IR window applications. Information on the microstructure, optical, and physical properties of the SPS spinel will be presented and compared with spinel produced using HP and HIP methods.
Glasses for Multiband Optics: Daniel Gibson1; Vinh Nguyen2; Daniel Rhonehouse2; Adam Floyd2; Shyam Bayya2; Jasbinder Sanghera2; 1563882; 2U.S. Naval Research Laboratory
NRL is developing a verity of new glasses that transmit across a wide wavelength range and have unique dispersion characteristics. NRL-series moldable glasses transmit SWIR through LWIR and may be bonded to each other in an adhesive-free thermal process. NRL-200-series glasses transmit visible through MWIR and expand the glass map for multispectral lens designs. These new materials enable greater flexibility for designers of lenses for advanced defense applications and potentially reduce the size, weight and cost of next-generation optics.
Study of Silica Glass Structural Properties under Compression Shockwave Using Reactive Force Field: Ashish Yadav1; Vaibhav Bihani1; N.M. Anoop Krishnan1; 1Indian Institute of Technology (IIT), Delhi
Silica glasses are commonly used in optical systems and, during the manufacturing process, are subjected to shockwaves due to high-power lasers. Therefore, it is essential to understand the structural changes and damaging mechanisms due to the compressive shockwave. We have performed reactive molecular dynamics simulations on silica glass to study the structural properties of silica glass under compression shockwave. We show that the Hugonoit curves follow the trends as of experiment trends. In addition, we show that the short-range order (pair distribution function, coordination number, inter-tetrahedral angle, and intra-tetrahedral angle) and medium-range order (rings) are affected by the shockwave propagation through the material. The structural changes behind the shock front are due to compaction of tetrahedral units, coordination defects, edge-sharing tetrahedra, and reduction of large rings.
Chalcogenides and Chalcopyrites; Growth of Multinary Cystals and Glasses for Lasers and Hyperspectral Imagers: Narsingh Singh; Ian Emge1; Pooja Gautam2; Krishna Machuga1; Fow-Sen Choa1; Bradley Arnold1; Lisa Kelly1; Brian Cullum1; Raghaw Rai3; 1University of Maryland Baltimore County; 2Indian Institute of Technology, BHU; 3Applied Novel Devices Inc
Chalcogenide and chalcopyrite crystals and glasses have played an important role in frequency conversion (nonlinear optical NLO) and imaging applications covering visible, near–infrared wavelength, mid wave infrared (MWIR), longwave wave infrared (LWIR) and even up to Tera hertz regions. Availability of a single material to meet requirement of transparency, NLO coefficient, low absorption coefficient and power handling capability has been major unknown factors. For high power lasers using optical parametric oscillation (OPO) approach low absorption is required at the pump and signal wavelengths. A similar criterion applies for second, third and higher order harmonic generation spite of more than four decades of investments and promises on variety of phosphides and arsenides, there is no single multifunctional material which can meet these challenges. To overcome these problems, we have designed and investigated several thallium, silver and gallium based binary, ternary and quaternary chalcogenides with unusual properties for lasers and imagers.