Glasses, Optical Materials, and Devices: Current Issues in Science & Technology: Novel Processing and Functional Applications of Glass Materials
Program Organizers: Jincheng Du, University of North Texas; S. Sundaram, Alfred University

Thursday 8:00 AM
October 3, 2019
Room: A106
Location: Oregon Convention Center

Session Chair: S. K. Sundaram, Alfred University; Jingshi Wu, Corning Inc.

8:00 AM  Invited
Managing Laser Damage on Glass Optics in the National Ignition Facility (NIF) Laser: Tayyab Suratwala1; 1Lawrence Livermore National Laboratory
    The National Ignition Facility (NIF) at Lawrence Livermore National Laboratory houses the world’s largest laser system, composed of 192 individual, 40-cm-aperture beamlines and over 8000 large (0.5 m scale) optics. Over the past decade, the NIF laser routinely operates at fluences above 8 J/cm2 (351nm, 3ns pulse), roughly twice the laser damage growth threshold of fused silica glass. During this time, the cumulative power & energy (encompassing both the number of laser shots and the fluence of individual shots) has increased by >2.5 times, largely enabled by improvements in the laser damage survivability of these optics and by novel processes to economically repair and recycle laser damaged optics. The various damage mechanisms encountered during this time, as well as the advances in optical fabrication, post processing, and in-situ laser system use & design of the optics to mitigate these damage mechanisms, will be reviewed.

8:30 AM  Invited
Glass Composition and Temperature Effects on the Result of Ion-exchange Stuffing Process: Jingshi Wu1; Timothy Gross1; Charlene Smith1; 1Corning Inc.
    Free volume of glass has big impact on the surface compressive stress (CS) and the depth of layer (DOL) generated by ion-exchange stuffing process where small radius alkali ions within the base glass are replaced with larger radius alkali ions from a molten salt. Both chemical composition and fictive temperature (Tf) of glass affect free volume. Three series of glasses were prepared: one set has different levels of B2O3 with all of boron in three coordination; a second set has boron in four coordination and the third has mixed coordination. All glasses were also prepared with different Tf by changing their thermal histories. Higher boron content in glass slows down the K+ inter-diffusivity. Higher Tf glass, which increases glass free volume, also increases three-coordinated boron in various degree depending on the base glass composition. The details of Tf effects on the three series of glass will be discussed.

9:00 AM  
A Polymer Coating System for Inhibiting Contact-induced Damage in Glass: Gregory Glaesemann1; Donald Clark1; Michael DeRosa1; James Matthews1; Jennifer Lyon1; Kimberly Keegan1; 1Corning Incorporated
    Glasses and ceramics are limited in their ability to resist contact-induced damage. The penetrating object produces both elastic and plastic deformation in the brittle material. This subsurface plastic deformation creates sites for crack initiation while the applied or residual stress provides the means for starter cracks to extend away from the damage zone. The resulting crack systems can limit the useable strength of the material, so there is continued interest in methods for addressing the consequences of this kind of damage. In this study a thin layer of nanosilica-filled polymer coating is shown to reduce the severity of sharp cracks in the underlying glass. The means by which such a coating can affect the underlying glass include load sharing, fatigue effects and the shape of the indenting object.

9:20 AM  
New Moldable Glasses for Multispectral Optics: Shyam Bayya1; Daniel Gibson1; Vinh Nguyen1; Jay Vizgaitis2; Jas Sanghera1; 1Naval Research Laboratory; 2Optx Imaging Systems
    There is a strong desire to reduce size and weight of single and multiband IR imaging systems in ISR operations on hand-held, helmet mounted or airborne platforms. NRL is developing new IR glasses that transmit from visible to longwave IR to expand the glass map and provide compact solutions to multispectral imaging systems. These glasses were specifically designed to have comparable glass molding temperatures and thermal properties so that they can be laminated and co-molded into optics with reduced number of air-glass interfaces (lower Fresnel reflection losses). These new NRL glasses also have negative or very low dn/dT, making it easier to athermalize the optical system. Our multispectral optics designs using these new materials demonstrate reduced size, complexity and improved performance. The glass database is now available for distribution. This presentation will cover discussions on the new optical materials, multispectral designs, as well fabrication and characterization of new optics.

9:40 AM  
A New Method for the Continuous Production of Glass Nanofibres: Continuous Fiberizing by Laser Melting and Supersonic Dragging (CoFibLaS): Félix Quintero1; Joaquín Penide1; Antonio Riveiro1; Jesús del Val1; Rafael Comesaña1; Fernando Lusquiños1; Juan Pou1; 1University of Vigo
    The enormous interest in the development of advanced continuous nanofibers is propelled by the pursuit of materials with improved mechanical properties and functionalities. Here, we present a new method to continuously produce glass nanofibers, with diameters that range from 300 nm up to 30 µm and virtually unlimited length. Continuous Fiberizing by Laser melting and Supersonic dragging (CoFibLaS) is a novel process which essentially consists on heating the precursor material uniformly and extremely fast using a high power laser while, at the same time, the melt is rapidly stretched and cooled by a supersonic air jet. A laser beam shaping system was designed and set-up to precisely control the temperature distribution in the filament. A de Laval nozzle was designed to provide a coaxial jet that exerts a high tension localized at the molten segment of the filament. A preliminary analysis of the mechanical properties of the nanofibers is presented.

10:00 AM Break

10:20 AM  Invited
Borophosphate Glasses for Biomedical Applications: Richard Brow1; Parker Freudenberger1; Rebekah Blatt1; Julie Semon1; 1Missouri University of Science and Technology
    Borate-based glasses react in aqueous environments faster than do silicate-based glasses, and this faster reactivity have made borate glasses candidates for wound-healing applications. Like Na-Ca-silicate glasses, Na-Ca-borate glasses create alkaline environments when they dissolve in aqueous solutions. Na-Ca-phosphate glasses, on the other hand, produce more acidic local environments when they dissolve. The dissolution behavior of Na-Ca-borophosphate glasses can be tailored by varying the B/P ratio, to produce glasses with dissolution rates that depend on the nature of the borophosphate network, and that produce local environments that range from acidic (low B/P) to basic (large B/P). In this paper, we describe the relationships between glass composition, network structure, and dissolution rates, and review cell vitality experiments that are sensitive to changes in local pH.

10:50 AM  
Laser Spinning of 13-93 Bioactive Glass Nanofibers: Antonio Riveiro1; Félix Quintero1; Jesús del Val1; Rafael Comesaña1; Fernando Lusquiños1; Juan Pou1; 1University of Vigo
    Bioactive glasses are mainly used in bone and dental repair products in form of granules or a putty, if mixed with a binder; however, their potential application could be increased if bioactive glasses were transformed into meshes of micro- and nanofibers. Meshes of nanosized fibers have potential application as a 3D macroporous scaffold, can be used for nanocomposites, or in wound care as a bioactive dressing. In this work, we report the production of 13-93 bioactive glass micro- and nanofibers using laser spinning technique. The degradation rates and release rate of active ions were determined. The excellent bioactivity of the nanofiber is confirmed in vitro after tested in simulated body fluid due to the rapid induction of bonelike minerals onto the surface of the fibers. Based on this study, these meshes of 13-93 bioactive glass are regarded as a promising next-generation biomaterial for bone regeneration applications.

11:10 AM  
Microstructure Evolution in Quick-setting Dental Pulp-capping Materials Made from Calcium Phosphate and Sodium Silicate Glass Microspheres: Levi Gardner1; Jerry Howard1; Krista Carlson1; 1University of Utah
     Dental caries are the most common human communicable disease, affecting 92% of the population between 16 and 65 in the US, with as many as 50% of restorations failing by 10 years. Retreatment often threatens vitality of dental pulp, necessitating root canal therapy or extraction. Pulp-capping techniques may be employed to avoid these costlier operations. Dycal, the most common pulp-capping material, provides quick setting (10 minutes) and easy manipulation but leads to adhesion issues and dissolution over time. As an alternative, mineral trioxide aggregate (MTA) was created, which matures into a calcium-deficient hydroxyapatite but has a long setting time (2-4 hours). In order to combine the quick setting behavior of Dycal with the sealing and chemical durability of MTA, this research examined the physical and chemical behavior of calcium phosphate and sodium silicate glass microsphere mixtures. This work outlines the processes governing their setting, bioactivity, and ceramic phase formation.

11:30 AM  
Investigation of Femtosecond Laser Irradiation of Rare-earth Aluminosilicate Glasses: David Dobesh1; S.K. Sundaram1; 1Alfred University
    Aluminosilicates features incorporation of optically active trivalent rare-earth (RE) ions with excellent chemical and mechanical durability. Interplay between the structural framework of Si and Al connectivity with the inclusions of RE ions are suitable for optical and laser glasses. We report femtosecond (fs) laser irradiation of RE2O3 - aluminosilicate glasses which allow modification through composition and laser interaction. Rare-earth aluminosilicate glasses (RE2O3 = La2O3, Nd2O3, Er2O3, Yb2O3) were studied to correlate polarizability with fs-laser irradiation. Structural associations with cation field strength of the RE, including intermixing of glasses is analyzed with fs-irradiation. Characterization include Fourier-transform infrared (FTIR) spectroscopy, 27Al magic angle spinning nuclear magnetic resonance (MAS-NMR), terahertz time-domain spectroscopy (THz-TDS), linear and non-linear optical refractive indices measurements, fluorescence spectroscopy, and differential scanning calorimetry (DSC), were employed to analyze the series of glasses. We will present our findings on the structural-optical property correlations of RE aluminosilicates with femtosecond laser irradiation.